Have you deliberately decided to use wvdial? I would have thought that kinternet would be using kppp. Perhaps you could try the same settings using kppp and see what happens.
Sorry if this is of no use but good luck :-)
Looking at the settings when using kinternet, it appears to be using the wvdial.conf as a reference. Making changes in the wvdial.conf (57600 vs 115200) were reflected in the kinternet settings. I haven't found a comparable *.conf for Kppp yet. Playing with the AT&C* command in Kppp didn't help either (it doesn't actually turn off carrier check, but it was the only related AT command I could find). I picked up a Zonet ZFM5600 which claims to be a hardware modem. But, I've got to purge all the current AC97 settings from the system as they seem to want the same IRQ. Barry