For the Belgian Railways website, you need a pass cover number. Mobile passes don't have one but @Nanja can give you one.

Thank you, but I had not yet provided any of pass cover number. I will try to contact eurail pass about it.

This nr is I (capital i) with 7 digits. On some REServ systems it is not checked at all if it is the real one, but I dk if that would also apply to b-rail.

It is indeed a very often posted question and untill now -even after many such requests-noone at the office seems to have been able to decide to add it right in the mail with the confirmation, which would make life much easier (but probably let EUrail have a few less of 2€ surcharges for making REServations)

An I with 8 digits for Interrail and and (I believe) an E with 8 digits for Eurail.

Hi, if you did not receive a Pass Cover number yet, I can provide you with one if you send over your order number via a private message. Cheers,