Might be a bit tricky to assemble but I think this will work...
Try and rig a hot water bottle to 2 lengths of hose (clear fish tank hose should be fine) Stick the rubber bottle to the cool side of the enclosure. One side of the hose should go to a water pump... I am thinking a large aquarium pump should do... the other length should go outside for a length and then back to the pump.
What this "should" do is make a closed system of water. The water will bring heat from the cage to cool when it goes outside and bring cool water back into the hot water bottle stuck to the side of the cage and then start all over.
The only other solution would be to find a way to cool your herp room somehow.
Yah but have you ever smelled cheese? Some of it stinks eh?