Payment methods on sales orders

Dear all,

In CRM 5.0, I've a problem with payment methods on my sales order (billing tab): the value list is not activated (is empty) in my sales order type whereas with a standard sales order it works. It seems it is because the field Tax destination country is not determined automatically. The BP used is the same in both cases, so it is not a problem of master data.

I don't know what to change in my customizing as I've compared 2 sales order types and it is the same; For information we don't use neither tax determination nor billing, only pricing.

Many thanks for your help

Marjolaine