Dialing to RAS with callback

Hi, we are having problems dialing to a Hardware equiv.
RAS with call back functionalities.

Have configured XP to make outgoing and receive incoming
connections.

ERROR code was 619.

Senario:
When dialing to the RAS, userid and password was
authenticated. The RAS drops the connection (follow-up
with a call back), and XP immediately gave an error 619.
Seems XP does not accept call back functions.

Another finding was, by default the modem was not
configured to answer call. we have configured the modem
manually using AT cmd to activate the pickup call function
for the modem. However whenever the dial up is done, XP
disables the modem pickup call function.

can anyone help?

any comments is appreciated.

thank you