DTP delta after migration

Hi,

How do we set up deltas using DTP's after migration.

If the ODS/Cube already has requests in it loaded using 3.5 infopaks, when we migrate to 7 and start using DTP's the first request acts like a init with data transfer, how do we setup a process where the delta from DTP acts like a init w/o data transfer and then does delta from then on. I have seen through other threads regarding this, but im still not clear how to go about it.

Thanks

Sam