[USR-TC] 3 Com Security and accounting server

I need to migrate our dial-up users from the 3 Com security and accounting server to Cisco ACS. Ideally I'd export the users from the 3 Com product (access 97) and import in ACS but the password field is encrypted, anyone know how to decrypt this field? I'm not an access person - I've been searching the web and it looks like I need the "encrypt function (Formula) that encrypted your data" Any ideas? I've contacted 3Com via the company that provide my maintenance contract and they (3 Com) are unwilling to help. Thanks Steve