How does SafeNet MobilePASS generate passwords?
So I was finally able to work this out. The pin code isn't important and is simply used to decrypt the activation code locally (not sure why our server asks for it in that case).

The activation code is a base32 encoding of a seed where every fifth character acts as a checksum for the previous four.

The seed is then passed through KDF1 to generate the shared secret.

That is then in turn used as part of the HOTP algorithm.

You can see my reimplementation in python here: https://github.com/datr/MobilePASSER/blob/python/mobilepass.py