That’s normal behaviour when it comes to MSN/WLM and e-mail clients it detects. In the case of 7.5, it’s supposed to detect Outlook Express and events that happen on there, but since Windows Live Mail is a fork of Outlook Express, there must be some code in it that makes 7.5 pick it up anyway.
However, when talking about live e-mail notifications sent by the server, that isn’t possible. More specifically, it isn’t possible on 1.0 - 4.6, period, due to the authentication scheme used (technically, it expects the server to store the password cleartext to verify the challenge/response authentication the client performs, which could make those kind of e-mail notifications possible, but @valtron isn’t that crazy), however, with 4.7.2009 - 4.7.3001 (5.1), and 5.0+, it is possible, considering the benefits of them using an encryption layer to send the password to the server in cleartext, and I do have plans already set out for utilizing this for the idea of the Escargot server sending out (semi-)live e-mail notifications from the server in-session possible, and much more:
However, I think that the capability of Windows Live Mail supplying something of a similar nature can hold us over for now. 