Privacy issues with Yahoo or GMail on a work email enabled Blackberry?

[slickpoppa]

Here's the deal: I recently bought a Verizon Blackberry 8830 and the tech guys at my office installed something on it so that my work email is synched with my Blackberry. Now I'm not sure what they installed on it, but from the brief research I've done, Blackberry Enterprise Server seems to be the standard package.

Now I'd like to be able to use my Blackberry to send personal emails without there being any danger of them being read by my company. If I link my Yahoo mail account to the Blackberry messages application, is there any chance that my company would be able to see those emails, assuming they just installed BES? Is there any chance they could have installed sneakier software that would allow them to spy on me?

Also, and correct me if I'm wrong, I think Gmail gives you the option of installing a separate application on your Blackberry that does not route your email through the Blackberry message program. Would that be a more secure alternative? The downside to gmail program is that I don't think you get automatically notified about new messages and have to open the program separately.

Thanks in advance, sorry if these questions sound dumb.