Look. since i got confused with all this, look how it goes.
Go to your gameserver/data/multisell.
then open the 80057 file with notepad, and u will see a code.
For example this:
<item id="1">
<production id="6656" count="1"/>
<ingredient id="3470" count="5"/>
<ingredient id="4037" count="5"/>
</item>
6656 is the id of the item u get.
The ingredient id, is the item that requires to take the production id. Since u want 2 different items to get them there are 2 ingredient ids. The count number is how many required items the item needs. just change it yourself and //reload multisell from game