I tried to use rp3 to dial in to work. It worked fine when I initially set it up. But then I had some hardware trouble. After fixing it, I couldn't get 115200 baud to work and moved my modem from /dev/ttyS1 to /dev/ttyS0. When I tried to reconfig rp3, I ran into various weird problems. First, I ended up with 3 devices listed - /dev/ttyS0 and *two* entries for /dev/ttyS1. Deleting them took them off the screen, but when the device screen closed & reopened, the two ttyS1 entries were still there. When setting /dev/ttyS1 to the default port, *both* ttyS1 lines had an asterisk on them. The next problem was that no matter what I did to the dialup configs, rp3 always configed the device to 115200 baud, even after I set everything to 57200. It also wouldn't respect the tty set for the entry - it kept using ttyS1. I can't remember if it always matched the default tty or just always ttyS1. I observed these facts by looking at the pppd command line with ps. Finally, I wanted to fix the configs by hand, but the man page didn't say what files rp3 uses.
The rp3 configuration tool uses /etc/wvdial.conf and /etc/sysconfig/network-scripts/ifcfg-ppp* to do its work. I've been unable to reproduce the problem here in the office. Try shutting down rp3, removing /etc/wvdial.conf and /etc/sysconfig/network-scripts/ifcfg-ppp*, and see if things appear more sane.
No response for > 2 months, so I assume this was fixed in Raw Hide and 6.2.