You're not sending a the buffer, you're sending the first vector.size() bytes of a vector. Stop the code in a debugger, inspect the memory starting at &vect[0], and compare it to what you're actually recieving, and I think you'll find that your code is behaving correctly (in the sense that it's doing what it's supposed to, not necessarily what you want).
I don'tknow what ReadThisFile does, but you need to actually put the bytes you want to send into a buffer and use that buffer as the argument to send. FWIW, ReadFile would probably be at least as easy for what it appears you're trying to do. Good luck.
Either ReadThisFile needs to tell you how many bytes it read, or you need to get the filesize another way and extrapolate the length of the buffer