http://www.palm.com/us/products/smartphone...samail_faqs.epl seems to tell me that anything to do with "ActiveSync" is also using the words "Exchange Server 2003" which Horde/IMP is not .... I'm thiking that you're trying to accomplish somethng not actually capable in the feature set of that phone and it's programming ... though not more than a couple of minutes spent searching ... it would seem that POP andIMAP should work just fine, though, yes, I suppose that due to notmal assumptions made in the programming, the use of different domains could be seen as a but of a problem, yet it's not like this setup is rare at all.
I'm also making an assumption that the term "Hotsync" is not what you are trying to ask / complain about ...???
Note: there is also the description of having to use a web browser function to access HotMail, perhaps use the seme function to access the WebMail version of your SpamCop.net e-mail account ..??? Not the same, I know, but ....