Cannot approve calender request using mobile device.

We have several vacation calenders web parts on our existing internal Web Application. The managers are not able to approve these requests using their mobile devices.

As a test, I added a vacation request to the Vacation Request Calendar making me as a the supervisor. I approved the request using my mobile device, however, when I go back to the site I still see it as pending.

I did another test, however, I approved it using my computer. This time it shows Approved.

We use Exchange 2010. The Web Application is setup with NTLM authentication.

What settings need to be made/changed on our SharePoint 2010 Standard environment?

Daniel Christian (MCTS)