I am looking for the same thing, I saw a reply from @Nanja  and @Leo I believe they are able to give it to us - but only Monday-Friday during business hours. Here is hoping they see this thread and help us out :) 

I'm in the same situation here, not able to book any of the trains that I want on the website but they are all available through the SNCF website.

Could I please get my pass cover number @Nanja ?

Thank you,

Customer service can get you a pass cover number that can be used for the Belgian railways booking website (extra fee: 4 EUR per order)

In addition, you can book without a pass cover number via ACP Rail (extra fee for Thalys: EUR 3.40 per seat).

Hi @Camilo Silva, @jenn.hart and @James Denby Wilkes, can you please provide me with your order number via a private message? Thanks, 

I also need a pass holder number for each of the four mobile passes we have for our family traveling this summer.

The best is to contact customer service.

Hi FrD, if you can provide me with your order number via a private message, I can get you one. Cheers, 

I seem to have found myself in the same situation :( @Nanja you seem to be doing the lord’s work! Could  you please help me obtain my interrail pass cover number? I would be extremely grateful.

Kind regards,

Alexander

Hi Alexander. I provided you with one via a private message, just now. Have a great day! 

Thank you so much! Lifesaver 

Wow, this is exactly what I'm looking for! Trying to book my ongoing journey from Sunday onwards, can't book any trains in Belgium and France. @Nanja Could you provide me with a pass cover number as well? That'd be awesome!

I'll PM you with my order no

I've sent one over to you via private message just now, Steven.   Have a great trip ahead! 

Thank you so much, you made my day! (and it's only 9.30 am )

Also looking for our pass cover numbers. @Nanja I have sent a PM with our details. Hoping you can help or point us in the right direction.

Just passed one over to you Michelle Cheers, 

Fabulous! You have been so helpful!

@Nanja I cannot book any tickets or relate trips to my pass, because in the railplanner App is only the option paper Pass, but I have a mobile pass. Please help me as soon as possible, because I need  to plan a trip.

Bevor the update of the app it was okay, but now the app is horrible to use.

Thanks in Advance

@Nanja  Hey! I am also in need of pass cover number asap. I have sent you my order number in PM. 

@Nanja hI, I am also trying to book a train for Matabiau (Fr) - Narbonne (Fr), via b-europe and  am also in  need of a pass cover number for my mobile pass!

I’m in the same situation, @Nanja. Please help!

Trying to reserve my seats from Avignon Gate TGV to Marseille Saint Charles, but I need the pass cover number. Honestly, even with a 1st class rail pass, I’m struggling to reserve my seats for most of my travel. :(

Will drop you a PM with my order number.

Thank you!

@Felipe.iturrieta  is Nanja back in Offfice?  If not please provide the users above with the PassCoverNumbers. 

Exact same issue with me, needing the cover number for myself and my friends and I’ll join the @Nanja tagging train. I can rustle up order numbers but Idk how to pm people on this yet I cant figure it out.

Just wanna use the b-europe website why they make it so harddd

Hi all @Bahnhofsoma, @siggy, @Baobao Lee, @JFB03,

I sent you all private messages. Heads-up: Nanja is still unavailable.  

Cheers!

Hey! @Magdalena @Nanja I am also in need of pass cover number asap. I have sent you my order number in PM. 

Hi,

I'd like to make reservations for my trip in France, but I need a pass cover number and I've a mobile pass. Could you provide me with such a number? Looking forward hearing from you.

Thanks,
Leonie