Cartridge emulators are available. I run Race Tech gold valves in a set of TY250 forks which like the DT2, have 34mm Kayaba fork tubes. The gold valves took ages to get set up but are quite good now.
On another trials bike with TY250 forks I have fitted aftermarket (modern) damper rods made in the UK which worked great without any setting up required. They are made of aluminium, have slightly more travel than standard (about 5mm extra) and most importantly have much better damping action than the standard damper rods provide.
I'm sure either of those methods would also make DT2 forks work better for MX.