[R-sig-ME] post hocs for LMMs / GLMMs

[Kay Cecil Cichini]

hello,

i have several LMMs and GLMMs with 2 nominal fixed factors, f1: A,B,C,D 
and f2: 1,2. now i need inference on the differences of level 1 vs. 2 of 
f2 within each level of f1, or vice versa differences of A/B, A/C, A/D, 
B/C, etc. within each level of f2.

before i try with glht(): isn't it justified to examining the model's 
t-tests with re-ordered levels of the nominal variables, by
which each of this comparisons can be yielded by the different
parameterizations - this seems to be the most convenient way and till 
now i found no one to explain to me why this may or may not be valid.

best regards,
kay