That XMT can do DC- (DCEN) Tig..
Thick Sections of aluminum can be done this way with Helium gas and some special oxide removal techniques. Edit: Would be very tricky to try DC- aluminum welding on sections thinner than 1/8 inch.
Your XMT cannot do AC TIG welding of aluminum... But thats about the only thing it can't do... AWSOME power supply.
It can do GMAW of aluminum... Some of the newer ones are quite good on material down to 16 ga. (.063) with GMAWP add-ons.