Canada Post - Add a custom description while printing label.

functions.php

add_filter('wf_canadapost_request','wf_canadapost_label_request_callback', 10, 2 );
function wf_canadapost_label_request_callback($request,$order){

    $custom_product_description = 'My product description'; // This text might not exceed 35 characters

    $xml = new SimpleXMLElement($request);
    if($xml->{'delivery-spec'}->{'destination'}->{'address-details'}->{'country-code'} != 'CA'){ //if international
        $ref_no = $xml->{'delivery-spec'}->{'references'}->{'customer-ref-1'};
        $custom_text = $ref_no.", ".$custom_product_description; 
        $xml->{'delivery-spec'}->{'references'}->{'customer-ref-1'} = substr($custom_text,0,35);
    }
    else
        $xml->{'delivery-spec'}->{'references'}->{'customer-ref-2'} = $custom_product_description; 

    return $xml->asXML();
}