Sanel,
First thing to say is that autobaud rate on ANY modem is not reliable and for a robust system it should be hard set to a known value as a matter of good practice if not just to take it out as a variable in the system as another thing that could go wrong.
I do not have a WS with me to test but the result sounds a little odd. I would suggest sending AT at 500mS intervals until you get an OK response out.
Regards
Matt