i searched for "a5 trial" with google and found the following result :
A5.12 trial
http://www.fileplanet.com/85718/80000/fileinfo/3D-GameStudio/A5-Trial-v5.12-%5BEnglish%5D

i hope this helps ^^

get the C# wrapper:
for A7.85.4 and A8.30.4, Version 2.3.9
at http://acknexwrapper2.matthias-auer.net/ or visit the thread