Different FPS slowmotion

Good day everybody!

I would need an advise.
I'm still working on FCP6, but I think this doesn't matter.
Well, I'm editing a 23,98 fps video. I needed a slight slowmotion for a few scenes, so I shot them in 29,97 fps (which I know is a VERY slight slowmotion, but it's enough for what I need and I didn't have any other option).
Now, I made a 23,98 fps timeline, and when I add the 29,97 fps clips, they need a render, and, after that, FC reads them as 23,98 fps clips. So, how can I obtain that little slowmotion a video with more fps should have?

Thank you very much in advance!

Two articles I wrote so long ago I almost forgot they still existed. Not sure if this answers your question or not.
www.eventdv.net/Articles/Editorial/Tutor...o2c-Part-1-50474.htm

www.eventdv.net/Articles/Editorial/Tutor...al-Cut-Pro-50949.htm