[BioC] Converting Affymetrix (*_at) Mouse Probe ID to HUGO gene symbol

[Gundala Viswanath]

I have the following list of probes (from Mouse),

1460644_at
1460645_at

The longer list can be found here: http://dpaste.com/1371949/plain/
What I want to do is to convert that name with HUGO gene symbol using
R. What's the way to do it?

I tried this but failed

__BEGIN__

library(biomaRt)
dat<-read.table("http://dpaste.com/1371949/plain/")
probes<-as.vector(as.matrix(dat))
mouse = useMart("ensembl", dataset = "mmusculus_gene_ensembl")
g = getGene( id = probes, type = "affy_mg_u74av2", mart = mouse)
show(g)

__END__

It prints Ensembl gene id instead (e.g.ENSMUSG00000057666)