One of the main selling points for Chinese arms is that they come with no strings attached, as such, I doubt Sudan or the UEA would have needed to get Chinese permission for those weapons. Which in turn is probably one of the main reasons why the rebels are getting so much Chinese kit when their Saudi and Gulf backers have plenty of European and US weapons, which would be easier to acquire and supply to the rebels than Chinese kit none of those countries actually use themselves.
However, because this practice is well established and well known, I doubt Assad would find much to fault China for, since he probably has also benefited from some no strings attached Chinese arms himself at some point.
With regards to training, yes, HJ8 missiles are complext pieces of equipment and it takes a bit of training on their maintenance, set up and use, but no more than the kind of training needed to operate FN6s. I would imagine that whoever provided the missiles would have also provided training to the crews, likely out of the country.
At this point, I am no longer shocked at advanced light Chinese weaponry turning up in rebel hands in Syria, as these now seem to be the weapons of choice for foreign powers to supply to the rebels with, to avoid leaving hard evidence of their meldling as would be the case if they supplied western weapons, which are more tightly controlled and tracked after they are sold and delivered. If advanced western weapons started turning up in Syria, it could raise awkward questions.
Mind you, all these videos of Chinese weapons scoring kills in Syria are good advertising for China, and I think western arms manufactures are getting envious, which is why there was so much pressure by the UK and France to lift the arms embargo on Syria so they can supply weapons to Syria, and the US was quick to jump on hat opening. So I fully expect to start seeing western ATGMs, AMRs and other light weapons start turning on in Syria.
