You'll have to adjust the UI and resolution to your liking in the web admin.
The JavaMO article in the wiki mentions this:
Go to the Orbiter in the pluto-admin web interface (select Orbiters in the Wizard on the left) Adapt the PK_UI, PK_Size and resolution values to match your phones display. If you have no touchscreen on the phone stick with symbian for PK_UI, otherwise choose the normal variant.
So, if you select UI1 as your UI, I think you should be able to use the touch screen. You will have to both regen your orbiter and reload after the regen has finished to apply your new selection.
br,
sambuca