hmm. it seems to me that most trial versions of expensive software that i have seen have always disabled things like save or export so that the program is basically unusable other than to toy around with. unless of course you want to crack it i guess. there is gmax which is a free version of 3ds max. of course you can only save in gmax format unless a game developer pays 3ds to add a plugin to the program, but otherwise plugins are disabled, too. there is a cracked 3ds out there too. and maya...if you are just trying to learn new techniques, etc. there is the maya 5 PLE you can download >here< . gmax is >here< . the maya PLE is their equivalent to a trial, so i don't know what will be disabled. just some suggestions.
Edit: i would not advocate downloading the cracked versions of such expensive software.