I'm using the Subversive plugin for Eclipse/Flex and I can commit the files correctly, but I have to rebuild Data/Services each time and reconfigure return types for each, etc. Does Subversion not provide a way to check/in out Data/Services or must these be rebuilt each time?
If I understand your comment to your question correctly, then it seems to me that it's not a problem of Subversion/Subversive, but a problem of Flash Builder's code generator which is generating/overriding your customized return types.
Maybe there are some Flex project settings files that are not committed. That would explain why you need to rebuild Data/Services each time you open the project.
By the way, if you do commit the project settings files, make sure all the paths are relative paths, so that the project settings can be shared among several developers.
You might find value in this Adobe devnet article about Flex project settings
My partner and I had different local names for the project we were working on so we had conflicts with the settings file.