Hi Nicolas,
You can use the Segmented Algorithm. Create each segment as Alphanumeric and take length of segment as 4.
For each segment, for each character, define the range of mask values as 0,0.
Just tested this and works fine :)
Number of segments you will need to define will depend on the longest length you expect to handle. So, for instance, you expect the longest length as 26, then, you should define 7 alphanumeric segments, each of length 4, and within each segment, for each character define range of mask values as 0,0
I hope this clarifies.
Regards,
Mayank