We report observations of the Cabibbo suppressed decays B --> (DK-)-K-(*) u
sing a 10.4 fb(-1) data sample accumulated at the Y(4S) resonance with the
Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios o
f Cabibbo suppressed to Cabibbo favored branching fractions are B(B- --> (D
K-)-K-0)/B(B- --> D(0)pi (-)) = 0.079 +/- 0.009 +/- 0.006, B((B) over bar0
--> D+K-)/B((B) over bar0 --> D(+)pi (-)) = 0.068 +/- 0.015 +/- 0.007. B(B-
--> (DK)-K-*0-)/B(B- --> D(*0)pi (-)) = 0.078 +/- 0.019 +/- 0.009, and B((
B) over bar (0) --> D*+K-)/B((B) over bar (0) --> D(*+)pi (-)) = 0.074 +/-
0.015 +/- 0.006. These are the first observations of the B --> D+K-. (DK-)-
K-*0, and D*+K- decay processes.