Skewed Bridges & Bounding Cross Sections

[BLBECKMAN878]

I AM TRYING TO MODEL A SKEWED BRIDGE IN HEC-RAS AND MY QUESTION IS HOW TO CUT MY BOUNDING CROSS SECTIONS. I THINK I'M SUPPOSED TO CUT MY BOUNDING SECTIONS ( 2 & 3) PARALLEL TO THE BRIDGE AND THEN ADJUST THEM FOR SKEW, BUT IT DOESN'T SEEM QUITE RIGHT TO CUT CROSS SECTIONS THAT AREN'T PERPENDICULAR TO THE FLOW? ALSO DO I CUT CROSS SECTIONS 1&4 PERPENDICULAR TO THE FLOW OR PARALLEL TO TH BRIDGE?

THANKS IN ADVANCE FOR YOUR INPUT