The "Intersection Curve" option on the Trim Surfaces Tool is missing.
In Microstation V8 XM Edition the Intersection Curve was an option on the Construct Trim Tool.
Tools > Surface Modeling > Modify Surfaces > Construct Trim > Intersection Curve
Intersection Curve has now been separated into it's own Compute Intersections toolIn V8i, this tool now available as its own tool and on the Surface Utilities Toolbox.
Tools > Surfaces > Surface Utilities > Compute Intersections