avoid invisible characters in Project coding Mask (SAP ECC, Project System)

Hi,

Someone faced problem with WBS Coding mask with invisible characters, for example we have next masking - C.XX.XXX.XX.00.000.XXXXX

where C - capex, X - any character (alphabet/numeric), 0 -any numeric character?

Question - it is possible to restrict for X only alphabet character from A-Z and numeric from 0-9, to exclude (restrict for usage) any other symbol like space and , " ! @ # $ % ^ & * and other invisible characters from  character map, because some times peoples using data from excel and didn't check what they put to SAP.

Please advise.

Thank you,

Vladimir