Plastic Injection Runner using Derived Parts

Good day everyone,

 

I've created a derived part for a plastic injection runner, but it's not behaving as expected. The first image shows the original derived part, the second displays the outcome when I used it, and the third illustrates the desired result. I'm using the Swept Boss command, but it always forms a straight line instead of following my guide curve. Typically, our runner designs consist of arching lines, so I want the derived part to follow the sketched guide. Is this possible? Thanks in advance. I've uploaded the file in case anyone can tweak it. Thank you!