snipped-for-privacy@optonline.net wrote: (massive snip)
Nobody else said it, so I will- if OP can match the pattern and the color of the existing soffit (or find a scrap piece in basement/crawlspace/garage ceiling), cut the holes on the ground, snap out the old panel, and snap the new one in. (Assuming he can pinpoint where the holes need to be, of course.) If old panel can't be matched, take it down, make the holes, and put it back up.
Yes, I know, old panel could be well fastened. But most I've seen of the plastic variety are just sorta snapped into place. The debris I see on roadsides and in yards after windstorms would tend to support that. Only way to tell is get up there and poke at it.
I've found that trying to cut or drill 'floating' plastic in mid-air, is like trying to machine a spring.