Sensor Alarm Input to Pelco D/P Command

[Nelboy 0]

Hello,
An associate of mine has a patch of land with 3 or 4 old shipping containers in and a veggie patch, the land is away from houses so has no mains electricity. He's after a simple CCTV system to watch the containers and I've suggested something could be done with solar - be it 12v or 24v, I have suitable devices which can step up or step down the output. There is a basic DVR with only a relatively small HDD so would likely only be able to record a single camera at a decent rate - I have a Bosch MIC550 and a 360vision Predator available (and a Redvision X somewhere in my loft) but these are just the cameras so no official PSU's... and I also have a couple of complete Genesis wirelsss PIR systems with battery-powered PIR's and masthead receivers. The idea I had was to use the 360 Predator as it has a really good IR light and obviously has PTZ functionality, then the Genesis system set with a PIR above each container sending a signal to the masthead receiver so as to create alarm inputs for PTZ presents on the 360 Predator..... *BUT* the missing piece in this is that I require some sort of translator board which would take these alarm dry inputs and convert into a suitable Pelco D or Pelco P transmission sent over the RS485 line to the 360 Predator - and I say 'Pelco D or P' simply because then it can easily be transferred across should a different PTZ camera be used in the future.
In addition it would be ideal if the board had an onboard relay which could be set via DIP switches to run for a set time - this would be outside of RS485 control so would not operate with the Aux1 or Aux2 commands that some DVR's can send, instead only switching if the relevant alarm input has been triggered; the relay could be used to switch a couple of LED lights, or perhaps trigger some sort of 'voice box' recording (if there is anything around like that) - or alternatively the relay would latch and so could switch a zenon flasher which would keep flashing until the container with the solar system inside was opened and a manual reset button pushed. Such a translator board could also be useful for my home cctv, as a lack of such an item has prevented me installing the MIC550 before now.

I've attached an image of roughly what I'm after, the address on the board would be set the same as the camera (in this example it would be address 1, Pelco P, 9600 Baud)............ If such a board is not available to buy, how easy would it be to make one?

(I'm trying to do this on a budget so if it gets too complicated then the land might just end up with a couple of basic turret cams and reduced recording time/quality on the DVR. I've seen a page selling the Alarm/Relay add-on board for the official 360 Predator PSU, but it's price is out of range for this project)