down converting HD footage for placement on SD timelines

Hey guys,
I need some education here.
I've got some P2 footage shot with a HPX170 in it's setting 720p/24p which Media 100 Suite (v.1.1.2) sees as 720p/59.94fps.
Someone asked me for an SD (DVD) copy of it and in doing some reading, it seemed I could create an SD timeline and drag it over to it and Media 100 would downconvert it for me in a desired way (letterbox, crop, etc.) Not with this footage. I get "Can not place HD 720p 59.94 fps clips into a NTSC 601 4x3 program." I've tried creating various SD timelines at different settings within Media 100 and none of them will work. I assume the format of this footage is screwy and just won't let me do it. Now I know I can dub out of my AJA Kona LHi card to down convert to DVCPRO tape but I was just wondering "technically" what's going on and how I can deal with it.
Thanks in advance.
BOB