Agoutihead
Since no one else has answered your question, I thought I would take a shot.
Considering that the knife in question is relatively inexpensive, why not try it yourself?
If the blade was unhardened, you would just use chainsaw and triangular files.
Since the blade is already heat treated, you cannot use a normal file.
The tools you use must be harder that the blade steel.
A grinding wheel on a Dremel tool comes to mind.( dont allow the steel to get too hot )
Although power tools allow you to work faster, mistakes will happen in the blink of an eye too.
Shop around your local importer like harbour freight, Princess auto, Wal-Mart
I have found carbide/diamond grit abrasive sharpening rods very cheaply.
Find a pattern you like on another blade-assuming this is not a problem
When buying tools, see if the tool fits the shape of the groove
The biggest issues are to:
1. keep the same angle
2. keep the same spacing
3. keep the same depth
If you are highly skilled in filing handwork, this is not a problem.
However since you asked the question this is likely not the case.
Keep the same angle
Try to setup the rod similar to a Lanskey sharpener setup
Use your imagination; you can make this as simple or as complex as you want to
Keep the same spacing
Using a plain steel rod the same diameter as the abrasive rod, put something between the two rods at each end and tape the two rods together.
Let the plain rod ride in the first groove you have filed
and so on
Keep the same depth
Eyeball it
Or
Measure and layout lines so all filed grooves meet the same line
Stick a piece of tape on the blade and use it as a reference point.
Steve