importing passwords from different system - how to migrate

[scowby]

I have a custom-built user forum that I am migrating over into VBulletin (v3.5.4).

One issue I am facing is how to port all of the current user passwords over from the old system, which simply uses an md5 encryption of the password, and into VBulletin, which uses this additional "salt" field.

Since VBulletin uses an md5 encryption of the user's plaintext password along with this "salt" mechanism, is there any way to do this, since I don't have copies of the plain-text passwords for my users?

Or, Is there a way to get VBulletin to use a simple md5 encryption of the password only, and disable using the extra "salt?"

What is a good suggestion on how to migrate my user base into VBulletin given this password issue?

Thanks!!