Hi, I will close this issue in the pharo tracker:
13246 MNU RBArgumentNode>>key with parameterized Seaside 3.1 REST Method
https://pharo.fogbugz.com/f/cases/13246
the solution is to change #argumentNamesOf: to be:
argumentNamesOf: aCompiledMethod
^ aCompiledMethod argumentNames
(works of Pharo3 and Pharo4)
Marcus
