It's not Exchange, but the client...
I dislike it's come to this but it's true, the iPhone handles this over custom ssl ports just fine and I have not come across anything else that does. I do not know why. With the iPhone or iPod touch too I'd guess, you just enter your email address and password. It tries the regular ports and fails, and where you enter the server you enter your port like servername:customsslport and then you have full active synch abilities, synched email, all your subfolders, and the option to synch calendar and address book too.
I recently tried an android phone and looking for a solution, at this very site found out windows phones couldn't do this either... Developers have tried to give google this code correction but they won't accept it for whatever reason. I ended up using a tether to my old iPhone just to get decent ActiveSynch over custom SSL ports until I gave in and took back the Atrix for the newer iPhone, as my old phone was falling apart and was the older slower one. I've tried 2.1 & 2.2 Android phones and when you try to enter the port using server
ort syntax you get invalid server format or the save button just gets grayed out until you remove the port. There's a few buggy market apps that sorta work in a limited way. It's possible the Blackberry may allow custom ssl ports on Exchange synch setup too, but I don't know, only that Windows and Android phones had issues with this but it works perfect on the iPhone, so it can't be a limitation of Exchange exactly. I haven't run into any good desktop clients for this, but to access full mobile email, synching even sent items and pushing select custom folders, calendar and contacts the iPhone truly synchs all these fine by entering the same port you use for custom OWA ssl in the Exchange email setup. I wish even desktop Outlook handled custom ssl port synching this well, and I'm not sure how the iPhone does it, as it seems very lightweight.
http://xdaforums.com/showthread.php?t=602494
My ISP blocks all ports below 1024 so I had to setup my SBS2003 Exchange server to run on port 8080 (HTTP) & 4443 (HTTPS), which works perfectly (tested locally & on remote locations).
When I add the correct secure portnumber to the server address (ActiveSync > Tools > Configure Server Source), ActiveSync cannot find our Exchange Server. When I remove the portnumber everything works fine as long as I'm on my local network.
I enter it like this: exchangeserverdomain.com:4443
I have OWA running perfectly by using the same external server address:<port>, and all needed certificates are on my WM6 device (it's the HTC Touch Dual).
Seems like ActiveSync doesn't like portnumbers.
Any tips?