I just discovered PLANdbAffy, which is a handy way to see exactly where Affy probes are interrogating a gene.
Nurtdinov RN*, Vasiliev MO, Ershova AS, Lossev IS, Karyagina AS.
PLANdbAffy: probe-level annotation database for Affymetrix expression microarrays.
Nucleic Acids Res., 2010, 38 (Database issue): D726-730. PMID: 19906711
Thanks, to all involved!