Britishguy
All is not what it seems to getting a Malaysian licence. Sometimes it can be straight forward and sometimes not! Basically as you quite rightly pointed out the Malaysian licence IS based on the old British CPL or ATPL licences(now obviously supeceded by the JAA licence) but with added Malaysianism attached. The DCA likes to think that they are in control but as most of the exams come from the international division of the CAA at Gatwick one can only say that it's frankly a British exam as all the questions are set by British examiners.
The first thing to do to converting your FAA licence to a Malaysian CPL/IR licence is have a chat with a DCA examiner. Unless you have been offered a job with an airline desperately in need of pilots then I will bet my last dollar that you will need to do all the technical exams PLUS all the navigations exams with the added pleasure of performance A. The flying bit will involve multi engine flying to obtain your instrument rating. One word of caution though,whatever you get from the DCA ,have it in WRITING as they have the tendecy to misplace documents and not back up what they have said verbally.
Now, if you come to Malaysia with a JAA or British Cpl/IR or fATPL then the conversion is painless and very swift. I believe the only thing required is to do the local Air Law. This might be your best route as you have already sat some exams.
The DCA has a website and you can find this through google. I hope the above will prove useful and if you need any more info then don't hesitate to email me.
Goldwing2000