From Webster's dictionary:

Main Entry: trans·gen·der
Pronunciation: \-ˈjen-dər\
Variant(s): or trans·gen·dered \-dərd\
Function: adjective
Date: 1979

: of, relating to, or being a person (as a transsexual or transvestite) who identifies with or expresses a gender identity that differs from the one which corresponds to the person's sex at birth

— trans·gen·der·ism \-ˌi-zəm\ noun

Main Entry: cross–dress·ing
Pronunciation: \ˈkrȯs-ˌdre-siŋ\
Function: noun
Date: 1911

: the wearing of clothes designed for the opposite sex
So in one way, a person can be a crossdresser, but not transgender. I personally see myself and all that crossdress as transgender. If someone does not like it, then I guess they need to convince Mr. Webster to change his definitions