Currently RadMenu for Silverlight is not supporting keyboard shortcuts, however you can navigate with the keyboard between items using the arrows and Enter. We know that we have some gaps in our Section 508 support and we are working constantly to improve it. The bad thing is that I am not aware of any workaround for this issue. I have created a Pits item for your request and you can follow its progress here
Please, excuse us for the inconvenience. We have added points to your account for the suggestions. Don't hesitate to contact us if you have other questions.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items