Hi Bel,
Dredging through my brain for cultural stuff from years gone by ... I worked in Singapore, Malaysia and Indonesia for 2 years. Singapore is majority Chinese, with a blend of Cantonese, Mandarin and Hokkien speakers. I guess it depends on where your Cantonese guy is from (could be China, Hong Kong, Singapore or New Zealand for that matter. I met a guy in Singapore who was of Cantonese origin (parents) but had the thuckest [sic] Kiwi accent I'd ever heard in my life!! Had only live in S'pore for 6 months and was suffering severe culture shock!) Stories aside, here's my 2c worth:
* The "two hands" for business card... good.
* Generally speaking, Asian cultures are very quietly spoken. Try not to raise your voice, or get overly excited.
* Avoid physical contact, other than regular business practices - shaking hands etc. Touching is a no-no - especially on the head or shoulders.
* As far as working with a translator goes, remember to talk to "El presidente" when you are speaking. It's a very easy trap to fall into to speak to the translator, thus leaving your primary contact (and person you most want to impress) feeling like he is a spectator.
As
of troy mentioned, bowing is good, but don't go over the top. A simple lowering of the head will show enough respect.
Above all, be courteous and aware. The fact that you're willing to find out about these things means that you're already doing both of those things. Realistically, most common courtesies (?) will get you by - especially if you are on your own home turf.
Hope this helps! 
Hev
