  We construct a variant of Karoubi's relative Chern character for smooth,
separated schemes over the ring of integers in a p-adic field and prove a
comparison with the rigid syntomic regulator. For smooth projective schemes we
further relate the relative Chern character to the etale p-adic regulator via
the Bloch-Kato exponential map. This reproves a result of Huber and Kings for
the spectrum of the ring of integers and generalizes it to all smooth
projective schemes as above.
