Different kinds of internal (Università degli Studi di Milano) post-doc positions are available here:

• on the UNIMI (University of Milan) web site (english version):
  Post-doctoral fellowship (type A) and Research fellowship (type B)
  

• Bandi per la Ricerca (italian version, on this web site, about Research fellowship, type B)

Also available some external post-doc positions (on an other web site of the Department, page "Opportunity for Students").