How to use the below dataset in Mahout (cf)

Hi All,

I want to build a recommender engine using cf of Mahout with a dataset as below:
<user,car1-rating,car2-rating, ............carn-rating> where user is string value and ratings are numeric.

Mahout seems to support <userid,itemid,rating> with numerical values directly, but is there a way to support a dataset like above by building a custom FileDataModel?
Or do we need to convert the dataset to the Mahout supported dataset format?

I am new to Mahout.
Please provide me an example where possible.

Thanks in advance,
Naveen