You are confused and know not what you speak of.
There is NO built in formatting capability for CDR(W)s in XP. None.
Nada. Zip. The big zero.
XP masters discs; this does not require formatting.
Formatting is involved when one wants to be able to read/write/erase
individual files on a CDRW (and to a limited extent, a CDR). For
that, you MUST turn to a third party application like InCD or Roxio
(Drag to CD? Is that what it's called now?). XP can't do that
natively.
Personally I steer clear of this UDF (packet writing) format as it is
not real realiable. It works fine until it doesn't, at which point
you are completely buggered and you have a CDR(W) that is completely
useless to you.