Remotely use latching relay from const + signal

Hi, I'm new here. I have searched through the forums and diagrams as best I can though, and can't quite find the solution I am looking for.

I have an irrigation project which uses 12vdc to drive the various components. The irrigation controller has relay outputs which are constant + , nc only. To turn on a valve, the controller engages the output, which drives a dc constant solenoid via direct wiring.

What I would like to do is take this [constant] output signal, remotely activate a relay base, which in turn switches on/off the latching solenoid relay. The part I am stuck on, is how do I use this remote relay to in turn activate the latching relay without bleeding power (has a small panel & battery )

Summary:
Remote relay- has nc,no. Has options for latch, toggle, momentary.
Latching solenoid valve- 90mA + to latch, - to unlatch.

I am by no means an electronic wiz; any help with this would be greatly appreciated. Can post pictures or diagrams of what I have thus far if needed.
Thanks

Apologies for the fact that this thread might actually belong in the relay category, but since it is essentially a wireless project, I thought it may fit here.

Apologies for the fact that this thread might actually belong in the relay category, but since it is essentially a wireless project, I thought it may fit here.

You can use a pager service and a time relay. If you got a 20 minute relay for instance, you'd just have to send the page every 20 minutes or however long you want it to run. I'd use a pager service because the signal goes further, is just one way, has more coverage in rural areas and most of all, it's cheap.

Thanks for the suggestion mcnugget. I hadn't considered that, though it certainly is an interesting idea. A couple of possible pitfalls that spring to mind tho; I am in Australia and our telecommunications network is quite different. While I do have pretty good coverage here, nothing is cheap. Also, there is a controller at the pump which is switching relays. I am using those outputs to send the signals. Typically, 1 valve will run for 4-8hrs then switch to another etc.

Since the time of this post, I have also solved the problem. At each unit, I have a small board, consisting of 2 relays, 2 capacitors, and 2 resistors. It is simply the "constant to momentary" wiring diagram listed here X 2. These 2 relays are connected to the rf relay base; 1 receiving signal from no, the other fron nc.
I have also been persuing the possibility of using arduino for this task. This would have the advantage of being able to provide feedback both ways; i.e. sending a signal back with "yes I am on, & everything ok".
Thanks again anyway

No problem. I can't imagine that radio modem and base station was any cheap. If you really really need to go cheap, you can use a prepaid cell phone. There's a way to hook it up so it switches your relays when it rings. Nobody will answer so it'll never actually charge you the minutes and if you get the right plan, the minutes never expire. So you buy minutes once and that's all you need.