Hi Dave,
i think i found it.
I use as a preliminary document type T- (meaning undetermined Customs status).
I do a GR.
In GTS, i have the WL of Determine Customs Status , where my GR Mat document appear and i set the Status to Duty unpaid , process the entry and the GR appear in the list for BWH entry...
If you have different method , let me know, but this one, will be ok for the customer, i think.
thanks again
Assen