  We use the results of hep-th/0007174 on the simple current classification of
open unoriented CFTs to construct half supersymmetry preserving crosscap states
for rational Calabi-Yau compactifications. We show that the corresponding
orientifold fixed planes obey the BPS-like relation M=exp(i*phi)Q. To prove
this relation, it is essential that the worldsheet CFT properly includes the
degrees of freedom from the uncompactified space-time component. The BPS-phase
phi can be identified with the automorphism type of the crosscap states. To
illustrate the method we compute crosscap states in Gepner models with each k_i
odd.
