I know this is fixed in the 2013 release as indicated in the link below but we are on 2012 Q2 and was wondering if there is a workaround to this issue.
http://www.telerik.com/help/silverlight/radmaskedinput-changes.html
I am already extending the RadMaskedNumericInput so I don't mind working with the templates or overiding some function if I have to.
Thanks!