My modem is on ttyS1. The default modem is set up to use ttyS1, and works fine with the debug command. The dialup profile is set up to use the default modem device, but still insists upon using ttyS0. Explicitly selecting to use the defined modem (the only one defined) allows it to use ttyS1, and work fine.
Please attach the contents of your wvdial.conf configuration file (with the sensitive parts -- passwords -- removed, of course). The contents of /etc/sysconfig/network-scripts/ifcfg-ppp0
Hrm... after reboot, switching back and forth works fine :P I'll try to do a fresh install and re-create the problem again.
Can't reproduce problem at all anymore under Beta 2.