Genotype importing from Sequenom

Sequenom has an odd format of calling a SNP genotype

gg
 [1] "C"  "GA" "A"  "C"  "C"  "AG" "C"  "C"  "T"  "G"

homozygous A is called A and heterozygous is called AT
The genetics package cannot handle the fact that some genotypes are declared
with 2 letter while other are declared with only 1. Consequently the
genotype() or makeGenotypes() will not work.

I need to either find a clever way that the genetics package actually does
do this. I think it may reside in the "method" argument but do not know how
to manipulat it. Alternatively I have to come up with some nifty string
manipulation. Any ideas?