I didn't know about swiss postal code, so I just did a search. Based on this document: http://www.swisspost.ch/pm-einschreiben-anleitung-barcode.pdf, it seems that the swiss post office makes uses of two standard barcodes with their own interpretation: Code 128 and Datamatrix. If that is the case, then we should already support them. If particular formatting is required, you may be able to set up some ADF rules for it.