My apologies for being so late in posting a reply, but I have been experimenting and learning for some months.
As it happens - I seem not to need the software / chip to trick the VP485.
Firstly, I bought a gravity-fed 24-tinte CISS (from Germany), and it seemed to work well for a while, but then the print quality deteriorated markedly, and it seemed to me it was not up to the job in terms of ink delivery - particularly when you do 260mm x 80mm ink-heavy labels, as I do sometimes. So I then sought out another CISS which did incorporate the bladders (as per the genuine VP485/HP88 carts) - and now this new one works fine.
I bought it from a very helpful place called JPL Blank Media - here in Melbourne - and I find it excellent. I purchase bulk Inktec inks very cheaply, and my print quality remains at a high standard (certainly high enough for my clients' needs). With this CISS, there are the same pressure bladders in the system as VP originals, so the VP485 printheads are fed enough ink, even when doing heavy runs.
So far I have not required any software tricks - I have just placed original VP chip-heads onto the CISS carts, and it is working fine. The amber light on the VP stays on constantly, and all the ink fuel gauges show empty but it doesn't seem to matter. I'm very happy with it.
Hope that helps.