I know there has been some problems with easily configuring the version of Android to use within Masa. I've straightened all this out in trunk. Basically, you can either just set the path(s) or you can use Maven toolchains:
http://code.google.com/p/masa/wiki/Toolchains if you want to flip back and forth between different SDKs. There is no longer a need to configure the android version in the maven-dx plugin config. The correct version is read from the android jar dependency in the pom.
As soon as I finish some work on handling of android resources over the next few days, I'll release 1.1.
Thanks,
Shane