Hi, Overwriting existing functions with new versions is done pretty easily by sourcing the altered versions. I tried the same for a S4 package method, but this resulted in an error message (complaining about arguments). The new method version is the old one but with an additional argument. THe method is ok, if I do not try to overwrite the old version but load everything fresh, it works fine. This is cumbersome for testing proposes, so is there another way to overwrite methods? A hint to a good link on S4 methods would be appreciated as well. Thanks, Peter -- "Ein Herz f?r Kinder" - Ihre Spende hilft! Aktion: www.deutschlandsegelt.de Unser Dankesch?n: Ihr Name auf dem Segel der 1. deutschen America's Cup-Yacht!