ITS transaction with SU05 and SU01

Question: Dear Friends,

I have the need to pass all my Internet Users from SU05 Master Data to SU01 Master Data.
My internet users use Internet Transactions through ITS server and, from what OSS service told me, if I use a SU01 user with 'kind of user = service' , I shouldn't find any problem.

So, I have deleted my SU05 User and I have created a SU01 'service user' , with the same name and the same password.
But when I try to use my Internet Transaction I receive the error "Internet user doesn't exist " ...

Where am I wrong?!?
How have I to do to pass my users from SU05 to SU01 ?

Thanks to all!!!

Max

Answer:
I have found out that all my Internet Transactions use the f.m.
BAPI_DEBTOR_CHECKPASSWORD to check the user and that f.m. needs SU05 users...

Anybody know any other f.m. that I could use to check Internet Users (debtors) on SU01 ?