created sales order in crm does not use userexit MV45 in r3 - why ?

Hello experts,

while creating an sales order in crm and replicating this order

into r3-system, the user-exit MV45 is not used in r3.

But when I create an sales order in r3, there system use the user-exit .

But I need this user exit, also the sales order is coming from crm.

Does anybody know why this is so ? Is there a solution ?

Thanks

Gerd