XML sample v4

lightbox4.xml

<?xml version="1.0" encoding="UTF-8"?>
<updates>
   <lightbox mediaset_id="87058" title="for-caroline" user_id="41967" created="2017-06-06">
      <media>
         <spl_number position="70">F018/2653</spl_number>
         <spl_number position="71">F018/2654</spl_number>
         <spl_number position="69">F018/3249</spl_number>
         <spl_number position="68">F018/3250</spl_number>
         <spl_number position="67">F018/3251</spl_number>
         <spl_number position="66">F018/3252</spl_number>
         <spl_number position="65">F018/3253</spl_number>
         <spl_number position="64">F018/3254</spl_number>
         <spl_number position="63">F018/3255</spl_number>
         <spl_number position="62">F018/3280</spl_number>
         <spl_number position="61">F018/3281</spl_number>
         <spl_number position="60">F018/3282</spl_number>
         <spl_number position="59">F018/3284</spl_number>
         <spl_number position="58">F018/3285</spl_number>
         <spl_number position="57">F018/3286</spl_number>
         <spl_number position="56">F018/3287</spl_number>
         <spl_number position="55">F018/3288</spl_number>
         <spl_number position="54">F018/3289</spl_number>
         <spl_number position="53">F018/3290</spl_number>
         <spl_number position="52">F018/3291</spl_number>
         <spl_number position="51">F018/3292</spl_number>
         <spl_number position="50">F018/3293</spl_number>
         <spl_number position="49">F018/3294</spl_number>
         <spl_number position="48">F018/3295</spl_number>
         <spl_number position="47">F018/3296</spl_number>
         <spl_number position="46">F018/3298</spl_number>
         <spl_number position="25">F018/3299</spl_number>
         <spl_number position="26">F018/3300</spl_number>
         <spl_number position="27">F018/3301</spl_number>
         <spl_number position="28">F018/3302</spl_number>
         <spl_number position="29">F018/3303</spl_number>
         <spl_number position="30">F018/3765</spl_number>
         <spl_number position="31">F018/3766</spl_number>
         <spl_number position="32">F018/3767</spl_number>
         <spl_number position="23">F018/3768</spl_number>
         <spl_number position="22">F018/3769</spl_number>
         <spl_number position="45">F018/3771</spl_number>
         <spl_number position="21">F018/3772</spl_number>
         <spl_number position="20">F018/3773</spl_number>
         <spl_number position="19">F018/3774</spl_number>
         <spl_number position="18">F018/3775</spl_number>
         <spl_number position="17">F018/3776</spl_number>
         <spl_number position="16">F018/3777</spl_number>
         <spl_number position="15">F018/3778</spl_number>
         <spl_number position="14">F018/3779</spl_number>
         <spl_number position="13">F018/3780</spl_number>
         <spl_number position="12">F018/3781</spl_number>
         <spl_number position="11">F018/3782</spl_number>
         <spl_number position="10">F018/3783</spl_number>
         <spl_number position="9">F018/3784</spl_number>
         <spl_number position="8">F018/3785</spl_number>
         <spl_number position="7">F018/3786</spl_number>
         <spl_number position="6">F018/3787</spl_number>
         <spl_number position="5">F018/3788</spl_number>
         <spl_number position="4">F018/3789</spl_number>
         <spl_number position="3">F018/3790</spl_number>
         <spl_number position="2">F018/3791</spl_number>
         <spl_number position="1">F018/3792</spl_number>
         <spl_number position="33">F018/3793</spl_number>
         <spl_number position="34">F018/3794</spl_number>
         <spl_number position="35">F018/3795</spl_number>
         <spl_number position="36">F018/3796</spl_number>
         <spl_number position="37">F018/3797</spl_number>
         <spl_number position="38">F018/3798</spl_number>
         <spl_number position="39">F018/3799</spl_number>
         <spl_number position="40">F018/3800</spl_number>
         <spl_number position="41">F018/3801</spl_number>
         <spl_number position="42">F018/3802</spl_number>
         <spl_number position="43">F018/3803</spl_number>
         <spl_number position="44">F018/3804</spl_number>
         <spl_number position="24">F018/3805</spl_number>
      </media>
   </lightbox>
</updates>

I've struggled to get that working. So far this works for inserting lightboxes, but not media:

<?xml version="1.0" encoding="UTF-8"?>
<updates>
  <lightbox juno_mediaset_id="87058" title="for-caroline test"
            media_type="S"
            user_id="41967"
            created="2017-06-06"
            notes="This is a test">
      <lightbox_medias>
         <media position="3" spl_number="018/3790" />
         <media position="2" spl_number="018/3791" />
         <media position="1" spl_number="018/3792" />
      </lightbox_medias>
   </lightbox>
 </updates>