Source and Target Issue

[sa0309]

I have a workflow that has 2 sources:

1. OraTable1
2. FlatFile

I run both sources thru a Union transformation then thru a Sorter transformation ( w/distinct ck'd to eliminate dups ). The output of my Sorter tranformation is input to my target table. Here's my issue, i want my Target to be a truncated version of OraTable1. In the session-task-mapping-target settings, I ck'd "truncate target table option". However; it appears the "truncate" takes place before OraTable1 is read as my source.

Basically i want to read OraTable1/FlatFile, transform, truncate OraTable1, then reload OraTable1. Is it possible to do this?

Any insight would be appreciated.

Thank you.