How to Import data to Custom Fields?

How to Import data to Custom Fields?

I have created about 5 'New Custom Fields' in the Accounts module
 
I now want to import data from csv to these fields.  However, I only seem to be able to map to a default set of Zoho CRM fields.
 
Looked around in settings, but can't see anywhere to change.
 
Help please! I like what I see from Zoho, but this could be a show stopper!