From what I can gather, it looks like Sunplus are suppliers of BD, DVD and Set Top Box ICs which can be fitted into any brand of component. If this be the case you'll need to search on brand of box for a compatible replacement, but be aware that most third party remotes probably won't cover all the functions of the original.

For the record, what is the make/model of universal you've tried? I've checked several Chunghop manuals and can find no listing for Sunplus.