I was able to do a workaround to solve my initial problem of how to dynamicaly create a user-defined mask by using a Converter.
Now I face a new problem in the same area with Sorting dates.
The default format of the date is "yyyy-MM-ddTHH:mm:ss" and I mask it to "dd/MM/yyyy HH:mm:ss" and it works just fine but the Xceed WPF DataGrid column sorting feature fails to sort the column correctly. It doesn't raise any type of error. It simply re-organizes the data in the table in another way but not correctly sorted.
How can I fix this?
Best regards, Gil