R – Looking to build a WPF XBap with full trust, can a purchased certificate get past some of the security issues

We are developing an application that needs to talk to some hardware (serial port) on the machine, and most of what we do is WPF and .net, so an xbap seems logical.

My concern is with the certifcates. I have seen a bunch of people showing how to create and self sign applications, but then the user is required to install that to their machine manual to trust the root. I am curious if we purchase an cert from say Verisign if that requirement will then go away?

I have no problem if there is a prompt requesting full trust, but I do not want my remote users dealing with installing certificates.

Thanks