Revit - Creating a Hatch inside a Rev Cloud

[ameador]

We are in Revit 2015, but have 2016 and soon 2017 in-house.

Question came up - they need a hatch pattern inside of a Revision Cloud.

Anyone know how to do this?

If I create a Rev Cloud, copy the line work, then create a Detail Line and paste in the linework and then try to select that for the hatch boundary, it gives me the box or line that is sketched inside of the cloud as the boundary.
You'll still see the cloud line work, but the hatch doesn't conform to all of the cloud arcs.

See attached image for what is created by this.

What I need is the hatch to fill in the whole Rev Cloud.