I'm not sure of an off the shelf addition but I've done something similar with a large carabiner. My initial intent was to use the carabiner with a loop of leather to turn hip sheaths into danglers but found the carabiner could work decently as a clip as well. It's a little awkward to get off but it seemed to work out okay.
Or, you could have a clip sheath designed of course. I think the BM puukko is too large but Collector knives large clip sheath might work for that. I've used it with a bradford guardian 3.5 and it worked pretty decent, along with a 3.5" blade puukko, but there was a lot of handle sticking out. If the handle is slim, it should work.
Here's what the sheath looks like. These 2 knives are smaller, but what I have using those sheaths for now.
They're currently only available in red.
https://www.collectorknives.net/sho...leather-fixed-clip-large-front-pocket-sheath/