First, have a good look at whats inside as it might be quite easy to figure out how it works. An AP015 current probe for example just uses a regular PCF8574 I2C port extender to control all of its innards, and an 24C02 for ID.
Oh, the ProBus has an pin (upper
right) that is connected to the BNC "ring" too, and many probes just use an resistor there to set attenuation. Same R values as for Tek and Agilent too. There also are "reserved" values that select wether it is an "intelligent" probe so the scope reads from I2C.
With some luck, all it would take is to connect that pin to the BNC ring on your tek.
At the moment, i am working on converting an Tek P5205 to ProBus (so the other way round), which does seem to be quite successful so far. The 5205 seems to run fine on +-12V (Tekprobe is +-15 but on the scopes i tested, it was more like +14 -14,5). I know i could buy an TPA10, just its way overpriced and i cant justify to pay 1k for something i can build for <5% of that price. Plus its interesting to see whats possible and what not, just as it is with all that software...
If your probe were a HVD3106, i would happily swap that P5205
and maybe even throw in that hugely overpriced TekVPI to Tekprobe adaptor.