You can do as Jim suggested an use an existing database table, although it requires the table to be in the Kentico database already. My suggestion would be to create the table you need without any of your custom fields from within the Kentico UI, then use the import toolkit to create the rest of the structure and import the data.
I used the "use existing table" function in v7 several times and found limitations to it. When I tried in v8.0.1 there were issues with it as well. I'm still not confident it's working properly so I stay away from it, plus you lose some functionality if you use Content Staging.