Signature Issue During The Retry

We use WM4.6 to send PIP with partners.
The problem – We initialed a PIP to partners.The first PIP is fine and also with signature but during the retry we noticed that the PIP is without signature and failed at partner site (For test retry setting ,partner blocked ACK ).
Is there any parameter should be changed?

What version of RNIF are you using? 1.1 or 2.0?