It sounds like you do not have the Telerik Visual Studio extension installed. This would cause the the issue you are stating. The Extensions for Visual Studio 2012 were released shortly after the controls were released and were not part of the same download. One thing to note is that Visual Studio Express does not support extensions
This is easily repaired via two different routes. I highly recommend choosing the first option, but the second option works just as well.
Option #1 - Use Telerik Control Panel
- Open the Telerik Control Panel on your machine. (If you don't have it, download it here and run it)
- Sign in with your Telerik account, the control panel will list all of your installed products in the left column.
- Select Windows Phone 7 and Windows Phone 8 check boxes
- Click "Proceed"
- Drop down the options under each product and select "Visual Studio 2012 Support"
- Click Proceed (after checking off the "I agree" checkbox)
The Telerik Control panel will now update any old files and also add in Visual Studio Support.
Option #2 - Install Telerik Extension through Visual Studio 2012
- Open Visual Studio 2012
- Under the "Tools" Menu, select the "Extensions and Updates..." item
- In the left pane, drop down the "Online" item and select "Visual Studio Gallery"
- In the search box in the right pane, type in "Telerik Windows Phone"
- You will see a "Telerik Windows Phone VSExtensions" search result
- Select and install that item
After you install the extension, you will need to do a Visual Studio restart.
You are all set! Let me know if this doesn't work and I'll dig deeper in the what the cause may be. If it does work, please come back and mark this thread as answered (to help anyone else who is having the same problem).