Import DTD with entity definitions

Hi:
I have a xml file using some entities, which is defined in a separate DTD file. However, when I try to define a Tamino Schema by importing this DTD, the entity is ignored. How can I solve the problem. Do I have to pre-process the xml file myself and solve all the entities according to the DTD before hand, and just import the DTD with the portion of entity definition removed?

Thanks