Another option would be to use the START_APPLICATION command from a .ui file to launch the browser. I started this thread to discuss the technique but didn't get a chance to try commands like "\My Flash Disk\op\Opera.exe" with an on-screen button.
Then for a button handler, you would use "run sc_launchExplorer" as the onrelease command:
.ui files to be modified is left as an exercise to the reader, I would assume navigatemap_800_480.ui or similar would work if you're adding it to a quick-launch bar (seen elsewhere in the forum).
I would think the appropriate executable to call would be a MortScript that
a) copies the driver DLL to \Windows
adds the required registry entries to enable the card (see MioPocket source as an example for this)
c) adds any registry entries required for opera.exe
d) calls opera.exe