It seems that the Treo is not able to switch back and forth between call-waiting calls. When a call waiting comes in you have the option to hang up and answer new call or hold and answer new call. When you are on the new call you only have a hang up or a 3-way call option. Is it possible to keep switching back between these two options.

Also during call waiting exchanges I have frozen a number of times. Does anyone else have similar experiences or ideas for how to avoid?