If you
go here there is a bit more of an explanation.
Here is the juicy part thats related to your question though:
Code:
Create Drivers Folder to move SP28737.exe file and move to that folder.
#> emerge cabextract
Installing CABExtract to extract inf files from .exe.
#> cabextract ./SP28537.exe
Extracting .inf files from SP28537.exe
So i'm not familiar with the process myself, but that should give you a basic understanding of the commands used.. good luck - and if this is enough information, mark the thread solved. If not, post some more questions and someone who knows more than i do will have to help you