Hi
Seems that you expect the value to populate automatically by referring it to ACGL_HEAD-SUMSOLL.
This is not going to happen unless you code for it. Referring to ACGL_HEAD-SUMSOLL will only provide a definition and not the value. So, create an activity step before it is required in the rule and then create a task (background and synchronous) ->method->coding to populate it-> pass back to WF in binding.
Regards,
Modak