pH has little to do with storage solution. The osmotic strength and the ions are the important features and vinegar doesn't even come close to cutting it. In most cases, pH probes employ a potassium chloride solution as the electrolyte and the purpose of storage solution is to replicate that environment on the exterior of the probe's bulb to avoid drawing out the ionic content from the bulb. I've seen storage solution molarity vary between 1 and 4 and its dependent upon the probe manufacturer. In essence, the storage solution molarity is dependent upon the probe's electrolyte molarity. So in a way, you should try and use the storage solution that the probe manufacturer recommends. If its a piece of crap probe, I wouldn't be surprised to hear of a manufacturer recommending the use of tap water. For good probes, use real solution.
With all that said, there are several sources that suggest that STARTING with a 4 buffer solution is a decent idea since it has very little ionic content and the low pH isn't a problem. The 4 buffer is also more stable than other higher pH buffers. From that starting point, add solid KCl to the buffer (or distilled water) to create a KCl solution of at least 2 molarity. For many probes, that should be close enough.