[QUOTE=mikec;407374]Did you see hypnotiks comment, sounds like some voodoo in the way you install cert
[QUOTE]

Yep i tried it according to hypnotiks comments and various other methods i could come up with, unfortunately no luck.

as i mentioned when i look in Webmail, in options > Mobile device,

i can see the N900 trying to connect, although all it says is

status : Ok
First sync on: 02/12/09 12:43
Device Id: the N900 Imei number.

however for the Nokia E90 there is additional information
Last successful sync:
User Agent: NokiaE90/2.07 Mail fo exchange.

so the attempt to sync from the N900 did reach the server, however its not able to fully sync.