Thank you for participating in the Slingbox Answers Forum. Below are some links that provide key troubleshooting steps to help out with the remote issue you are having.
Hope this Helps.
The Sling Moderation Team
Assuming you are using the built-in Remote then the reason some functions are greyed out is that Sling have not correctly mapped the functions to those buttons. Absolutely nothing you can do about that.
The solution is to use a Custom Remote that has all the buttons correctly mapped. Try this one: http://www.hifi-remote.com/forums/dload.php?action=file&file_id=6644