Studio spline - Origin curve selection

Hello All

I have to make a studiospline which passed over 4 different cross sections (1-Rectangular slot with oversized arc, 3-circule differnt dia), which are connected with 2 guide strings (In Attachments)

I'm using studio spline option to achieve it.

However i'm unable to winover the origincurve selection.

So I could not acheive the desired results.

Could you help how to make it work correct ?

Also, I tried between only two circles, there I get only one sided surfece along the path, eventhough my selection is to solid.

Thanks

NX10.0.3.5 TC10