Hi,

This can be done using a a drop down that is tied to the lookup control via the "Transfer Data" action. The drop down will be populated with fields you have set, then click on the lookup control and configure the "Transfer data" rule something like this:

"When the drop down is clicked/changed then Transfer Data to the Lookup control"

Also have a look at the following link:

http://help.k2.com/helppages/K2smartforms1.0.6/default.htm#SF_-_ViewControls_-_Lookup.html%3FTocPath%3DK2%20Designer%7CViews%7CToolbox%7CControls%7C_____10

HTH

Regards,

Yannick