Use Mustache in a webhook to link DeviceID to a service ID

I am trying to create a webhook that incorporates some way to link a particle device ID to another number to be used by the targeted webservice (in this example PVOutput).

Pvoutput wants you to add a systemID as a header to your query. Now I could probably program every Electron with its SystemID. But I thought the solution given here would be much nicer. I was wondering if it would be possible to use the webhook JSON to convert the Particle Device ID to a systemid for pvoutput. So we add an list of deviceids : systemids and use the moustache variable {{PARTICLE_DEVICE_ID}} to index the array. But this does not seem to be working.
Anybody got any thoughts on this issue? Another way to resolve this? Let’s assume that creating a webhook for every Electron is not possible, just as it is not possible to program the systemid into every Electron.

  "event": "pvLiveData",
  "url": "",
  "mydevices": true,
  "requestType": "POST",
  "auth": null,
  "ids" : 
		"00000000000000000000" : "00000",
		"00000000000000000001" : "11111",
		"00000000000000000002" : "22222",
		"00000000000000000003" : "33333",			
	"X-Pvoutput-SystemId": "{{ids.{{PARTICLE_DEVICE_ID}}}}",
	"X-Pvoutput-Apikey": "AAAAAAAAAA"

  "query": {
				"d": "{{d}}",
				"t": "{{t}}",
				"v2": "{{v2}}",
				"v5": "{{v5}}"

I just thought of trying to test this without varying Particle id, by changing the

"X-Pvoutput-SystemId": "{{ids.{{PARTICLE_DEVICE_ID}}}}",

String to

	"X-Pvoutput-SystemId": "{{ids.00000000000000000003}}",

And sadly that does not work. So probably no chance that further nesting would work. Anybody got any other ideas?