Has anyone successfully created ws-security headers using a VB client?

My web service authenticates users correctly when I use a .Net client
using WSE, however I am having problems constructing the correct
header using VB6.

I have a VB class that implements IHeaderHandler which I then set on
the SOAPClient HeaderHandler property. This works fine for plain text
passwords. However setting the Password element Type attribute to
wsse:PasswordDigest and passing the password digest just doesn't seem
to work. I have tried numerous ways of creating the password hash
from my nonce, creation date and password, however the digest always
seems to end up twice as long as the equivalent produced using a .Net
client with WSE. Can anyone help?

Regards
Mike Cook