In the business world, if you create material while on the clock, the employer has the rights. Now this is not hard and fast but in the entertainment industry, people who are writing scripts and story ideas make sure to do so in such a way that their employer can never claim it was done on the clock.
On the face of it, I don't think you really have much of an option. I'm sure it's a fantastic presentation but do you think it's worth the money to sue? In China? And worth the damage relationships?
It sucks but it seems like trying to take this further will only cause you grief with little reward.
BTW, I had a boss once take my work, that I'd won a statewide award with, and have the organization that presented me with the award, issue a new certificate with his name included. So I had a certificate that was presented at the ceremony with only my name and he had one that had both of our names. Pretty frustrating but I took solace in knowing that I could recreate that level of work and he never would.