Hello Arve,
We will provide in our next release a property named TextMaskFormat that manages the literals in the Value property.
For your version Nikolay's workaround is not suitable.
I would suggest that you wait for the new assemlies or to inherit MaskedEditBox and override the Value property in order to remove literal symbols. Please refer to the code below:
I hope this helps.
All the best,
Peter
the Telerik team
Q2’11 SP1 of RadControls for WinForms is available for download (see what's new); also available is the Q3'11 Roadmap for Telerik Windows Forms controls.