I am having some trouble positioning an inserted part into an assembly. In the Insert Component menu I may select the part and click the OK button which aligns the part with the assembly origin. That is right, front, and top plane of the part overlap with the right, front, and top planes of the assembly. Alternatively, I can select and drag the part into the assembly graphics area to some arbitrary location.

However, either way I seem unable to move the part once it is placed. If I try to mate the part to the assembly geometry in some other way I get an error. The error is that the component is fully defined and any new mate will be ignored. I would like to offset the part from the origin of the assembly in a precise way. Is there a way I can do this?