Multiselection items field for svcCat.disp.item format


I can click multiple items in a list of comfill field and each will be filled. This is only available when filling to an array field.

How to implement a field of multiple user choice, like List Builder control, for svcCat.disp.item format and save data of user choice. svcCat.disp.item format has no direct connection to the table. I can not put the comfill array field and the input variable for the List Builder control does not store the user's choice.