Note: These links DON'T relate directly to an Oka, but the VE pump is widely used on other diesel vehicles so the information is still relevant.
Oka manuals describe the pump and its removal in Section 3 of the Parts Manual and Section 12 of the Service Manual. However, there is no information in these manuals on repair or overhaul of the injector pump.
If any of this information is not accessible, I have downloads of all these sites on my computer.
A Bosch overhaul kit is available at around $120 which contains all the seals and minor overhaul parts but no information on how to do it.
I have replaced the throttle shaft seal in-situ (see this link) but I have not yet actually removed a pump.
Please advise if there are other resources I can add to this list.
Bosch book on the VE Pump (This is an original Bosch 64 page Technical Instruction Manual in pdf format.)
Parts Listing (This is a breakdown of the pump components. Click on an item under Pump. Parts to show photos and highlight the item on the diagram.)
VE Injector Pump Assembly in pictures (This is a a larger website with lots of photos. It takes a long time to load but is very informative.)
Peugeot Diesel Pump upgrade Part 4 (This covers Boost Adjustments)
Peugeot Diesel Pump upgrade Part 5 (This covers Final Tuning of the Injection System)
Dodge 50 Perkins (This includes 10 pages from the Perkins Service manual)
Priming the pump (A simple set of instructions)
Resealing a Bosch VE Injection Pump (A step by step approach to replacing the rear distributor head O-ring seal without dismantling the pump. However, it does require removal of the pump. I doubt that it's possible in-situ.)
Description of the Bosch VE Injector Pump (This is a very useful description of the pump operation. However, it's still a work-in-progress so not all the diagrams are yet present, but those that are there can be enlarged)
VE Pump Power Adjustments 1 and VE Pump Power Adjustments 2 (These sites show how to make some small power/fuel flow adjustments. Note the warning messages.)
Google Book Search on VE Pumps (This is a Google Books search. It returns many books relating to the Bosch VE injector pump, some of which can be reviewed on-line.)
Google Image Search on VE Pumps (This is a similar search but for images. They might well lead to more informative web sites.)