I don't have the Serial programmer so I can't test it, but unless I'm wrong, I'm afraid there isn't any help as such; converting the Basic program into Assembler doesn't allow the use of the PWMOUT command, along with a number of others. See AXE001_bas2ass.pdf - although PWMOUT isn't listed there ...
<i>"This feature is designed as an educational tool rather than a professional
development feature. Consequentially, at present, not all BASIC commands are
supported. In later releases more commands and features may be added". </i>