Caching key

[Walsh, Peter]

Hello,
I am trying to determine what URI ATS uses as the key to cache the response 
data.  Is it the incoming URI or the remapped URI?
Meaning, if I map "exernal.com" to "mapped.com", is the response cached with 
the remapped "mapped.com"?  I believe this to be the case but want to be sure.
Thanks in advance,
Pete