Loading external phone apps

Hi,

Perhaps I should go through the online manual again, but I'm kinda lazy,
rather impatient.

It is possible to launch the web browser using the Phone Lib, such as
StartActivity(phone1.OpenBrowser("http://..."))

Now, my phone came with an HTMLViewer program, which is light-weight
and simply displays HTML code formidably.

Question being, how to load external apps with parameters?

Cheers

Robert