I have a BB 7290, non-BES. I want to use IM. I have read the BlackBerry FAQ and have done a search like we are supposed to

and am concerned about using VeriChat or other 3rd party IM software due to the T-Mobile port blocking issue. The FAQ suggests a solution of using a hosted BES but that of course is more $$ just for IM functionality. Has anyone tried the T-Mobile IM software which can be downloaded at
http://software.se.t-mobile.com/? I assume (maybe foolish me) that T-Mobile would not block its own IM client, and that client seems to support most (though maybe not all) of the major IM services? Any opinions/advice on that client, or whether the port-blocking issue still is an issue? Thanks!