Didn't you ask a related question the other day, and didn't I tell you to use character format?
I don't know about what the native format from Sybase looks like these days, but you would need to have quite bit of luck if you could import them directly with the BCP from SQL Server.
If you insist on using native files, you will have to write your own program. That is, you will have to find out what the native format from Sybase looks like. If you need help with that, you need a Sybase forum.
Well, who knows, maybe someone has written that program, but I am not going to Google that for you. My recommendation is that you use character files.