What's the best method to develop Series 60 apps?

I've been using the different Series 60 SDKs (v1.0, v1.2.1 and v2) along with the Sun WTK but it only kind of half works. I get error messages along the lines of

"WARNING: Attribute value for MicroEdition-Profile defined in JAR manifest is not supported."

Is there a better way to go about this? Is there not a specific emulator for the 7650 like there is for the (series 40) 7210?