This is what I had to do to be able to return a casa table from a measures tool method.
1. I edited casa/code/xmlcasa/xml/conversions.xml adding the following tag near the beginning of the file with like tags:
>substitute interface="casatable" as="table" in="measures" />
2. I added the following element as a child of the root
element in code/xmlcasa/implement/measures/measures.xml
3. I gave my function a casatable returns type
4. I implemented a corresponding method with a
return type in code/xmlcasa/implement/measures/measures_cmpt.cc