List Item does not show in workflow actions "Set Field" or "Update Item in this list"

Hello,

I have a simple List and have an Approval workflow on that list. I am not using InfoPath yet so the form used to fill out the list is the basic Sharepoint form.

In the workflow, I ned to update one of the columns in the current list. However when I use the Set Field to value ot Update item in this list actions, only the Tile and a few other fields are visible.

I am using Sharepoint 2010 and the workflow is a Reusable workflow on a Content Type.

Please let me know how I can update that one field.

Thanks,

Summer