In our Ultimate Windows Phone 7.5 Mango Preview, we were unable to get multiple Google calendars to show up in the new Windows Phonen Calendar app. Since Google uses Exchange Activesync for their push calendar, contacts, and email features on mobile devices, and since Microsoft has broadly enabled multiple calendar syncing on Windows Phone Mango, you would think that it would just work in the same way that it does with Windows Live and regular Exchange accounts. As it turns out, Google doesn’t allow Windows Phone users to manage which calendars sync with their devices.

Luckily, Anthony (the developer of Wonder Reader) has found a work around that will allow you to enable multiple calendar sync! Check out his full tutorial here. Basically, his work-around shows you how to make your PC version of Apple’s Safari appear to web servers like an iOS device so that you can get Google to load the page where you can configure which calendars will get synced to your mobile device over Activesync.

Hopefully, when the Windows Phone Mango update is finalized, Google will enable this functionality instead of requiring this work-around. In the meantime, if you’ve got a beta version of Mango and you need some multiple Gmail calendar syncing action, try it out!

Source: Wonder Reader via Windows Phone Secrets