Now i have a solution that works (for me).
I use javadoc.exe, because i only need the xml file and have the final jar already.
But javadoc needs the java source files. And the Oxygene compiler creates only the jar file, my source files are pascal syntax.
The solution:
A java decompiler (cfr_0_76.jar) creates me the java source files from jar.
Then i created a python script which transfers me the comments and correct parameter names from pascal source to java source.
Finally javadoc creates me the xml.
All three steps runs from a batch file, the lib and source file names will be automatically identified.