You can use a couple of TANGS events and an ARC event to approximate an ellipse, but if it has to be more accurate, I think you will need to use a CAM package to generate it.
I'm not familiar with Bobcad, can you break the spline into lines or arcs?
If yes to lines, save as a DXF file and import that.
If yes to arcs but not lines, create lines at arc endpoints, save and import.
I use Mastercam so I just created the ellipse, broke it into arcs, created the lines, exported the DXF, imported the DXF into FastCam, added the Start and End events, and verified the program. It took me about 30 minutes to get the 227 event program.
Its not difficult, just time consuming.