Corporation product selling

I just conquered a new country, and selected the option to TAKE the country, now if I want for the corporations to sell their products directly to another country what do i do?

Something like:
MAIN COUNTRY --- Products --- CONQUERED COUNTRY
[==Storage==] <---------- [==Corporations==]

Go to the corporation page for each corp.
Scroll to the bottom.
Click Review corporation contracts.
Click propose a new contract to countries or their corporations.
Enter the name of your main country and fill in the details on the next page.
Switch back to your main country and accept the contracts.

Generally, this is not an advisable thing to do. You may not need the full production from all the corps and they may make more profit selling on the open market (boosting the finances of the conquered country which can be transferred back to your main)