fileupload and memorystream

Hi:
I meet a problem when reconstructing a new memory from fileupload's postfile inputstream, 
like followings:
MemoryStream ms = new MemoryStream(this.fuload.FileBytes); the main problem is, is the upper code snippet is the deepcopy of fuload's fileBytes; (fuload is a fileupload instance).
and how to clean the fuload.FileBytes, to make sure the ms is not build its stream by call by reference, instead, is the deepcopy
Thanks a lot.