We just find maybe a firmware bug:
Setting the baud rate to 19200 and saving default profile doesn`t works, after a power off the modem starts at 115200 baud:
AT+IPR=19200 ( then change HyperTerminal to 19200)
AT&Y0 (profile 0 is the default after reset)
AT&W0 (save parameters to profile 0)
Then power off the modem, and...
Setting IPR=0 (autobaud) works fine with the same procedure.
There is no problem with the other parameters.