Rafter Flush Cut at Bottom on Top of Steel Beam

[j2narchitecture]

Hello.

 

How do I trim the bottom of the rafter so that it is cut square to the top of the steel beam or a 2x plate on top of the steel beam?

Currently, the rafter is extending through the steel beam.  I have the beam set as a Roof Beam.

See area in Red circle.

 

Thanks in advance!