IP Office Server Edition R9 SP3 UMS not working

[allweather]

I have installed IP Office Server Edition release 9 SP3 on one server,a second server is runing Application Server (Linux)to give more ressources for One-X(VMPro and One-X), also there is a third server that is acting as a back-up Server for IPO, VMPro and One-X. Mapi cannot be used since SMTP is configured on both Application Server and Back-up Server for VMPro back-up. All phones used are 9611 (in all 700 of them). Customer is using Microsoft Exchange 2010 and wish to use UMS Exchange and I cannot get this one working. It looks like MAPI is required in order to have UMS working properly.

Does anybody know if this configuration can support UMS Exchange and if yes what type of configurations are required.

Thanks for your help !