Devise is an awesome gem. I recently used it with an iPhone application that I'm building, but I found a limitation when making remote authentication requests via xml. So what is one to do?

Fork it and fix it!

The XML mappings as well as some of the core lib's did not account for new registrations via xml. I still have yet to finish it off by writing some tests, but I will do this soon and send a pull request to the maintainers.

In the mean time, if you have the need to do remote registrations via XML to the Devise gem, check out my github fork.