2010/9/21 dotnetdub dotnetdub@gmail.com:
This substitution works fine but when I read $pU it still has the leading 0
Yes, the change is just applied when the message leaves the proxy.
What is the best way to achieve what I'm trying to do?
I recommedn you to first delete the PPI header with hf_remove("P-Preferred-Identity") and later generate your own PPI header (hf_append) by reading the content of $pu (which still has the original value arrived to the proxy).