No one can help you based on that little information.

Maybe with the brand and model of the DSS receiver someone could help you. You might need to put that brand and model in the subject of your post (which I think you can edit) to get the right people to notice.

Why do you need help with just those two buttons? Did you get HEX codes for other buttons from somewhere else?

Posting some HEX codes for buttons you have would actually do even more than brand and model for telling us what IR code set it uses, to help find the SD/HD codes.

Also, I assume you only want discrete SD and discrete HD (not a toggle or round robin signal). If the original remote has toggle or round robin, maybe the discrete codes don't exist and you need to be thinking/asking about work arounds.