iccs is a complex survey (see chapter 3 of the user guide) and the R survey package cannot (yet) handle multi-level models - you can read the bottom of this post for more detail
if you don't care about standard errors, most of the functions in lme4
have a weights=
argument that should give you reasonable guesses.. but the standard errors will all be wrong.
the iccs 2009 user guide recommends other software on pdf page 33 of 112.