I have a trading partner who's ONLY implementation of message encryption includes PKCS5 Padding. I have been trying to figure out if this is supported on the AS2 server or not. I have never had a problem with other trading partners and in the past I have traded with this partner but now I am having problems and based on the searches I have done it seems to point to the message encryption.
if the padding your partner uses is uncommon for 3DES and AS2, why don't you change to AES? PKCS#5 should not be possible there.