Physical characteristics of non XML docs

I'm new to XML schema so forgive me if its a silly one.

Because XMl Schema gives a means of describing a document and its logical
structure I thought it also be a good choice to describe a
non XML bitstream / file and give it additional physical characteristics. 

For example the bitstream can contain 2 byte, 4 byte integers which will
have characteristics such as endian type depending on the platform they come
from. Also strings in the bitstream may be of varying codepages and lenghts
so there are additional characterisitcs for potentially every element or
attribute type. 
Can a schema be used / appended to to give this type of physical (or user)
extras or is there another recommended approach.

Thanks
Cormac Keogh