Berbee, a Cisco Partner, has free XML phone services it hosts for Call Manager at http://www.berbee.com/public/berbeesoftware/XMLFree.aspx
Phill B a Network engineer at Global Knowledge did a little investigating and found how to limit the options available to end users by doing the following from the command line :
to enter the required question mark character in IOS. In order to enter the question mark as a character and not a calling IOS help you have to use the sequence: Ctrl+v and then enter the question mark, then enter the remaining characters, that works