Sourcing : can't create a surrogate quote

 Hi, 

I have suppliers wich don't acces to Oracle Sourcing, So the Buyer want to create a surogate quote for them.

  

We don't find the supplier in the liste (in page create a surrogate quote) event if the supplier is invited to the negociation.  

when we create an Oracle User to the supplier, then he appear in the list  !   

is -it mandatory to create Oracle-users  to all suppliers even if we don't want them to acces directly to Oracle Sourcing  ?  

Please help. 

Thanks.