Symptoms
How to limit SharePoint access to lists when a workflow is kicked off.
Diagnoses
Information required to see if it was possible to create custom permissions on SharePoint list by removing all existing when a workflow is started, and have custom permissions take their place at time of execution.
Resolution
This functionality was included with the release of Appit 1.5. You should be able to configure accordingly. If for some reason this still is not working for you, please advise, and will keep this ticket open while we find a solution that can be agreed upon.
http://help.k2.com/onlinehelp/K2Appit/UserGuide/current/default.htm#Thin_Client_Wizards/Lists_Wizards/Lists_Wizards.htm%3FTocPath%3DCreate%7CWorkflow%7CWorkflow%2520Steps%7CWorkflow%2520Wizards%2520%7CLists%2520Wizards%7C_____0