You could also email these italian chaps as they seemed to do the software development, they were polite and helpful to me in the past.
http://www.power-one.it/digilab/Digi.aspx?Code=15Solutions are rather messy/expensive ....
- sniff/decode the 868mhz signal from the wireless signal aka rfxCom type solution
rather technical and if you could persuade power one to issue spec under NDA it would be a little easier
still fair bit off effort to design ardino wireless receiver then output to large display, presume you mean monitor/tv
- hook up rs485 and wire to a pc and write application to query the inverter
again an NDA to get the protocol would be needed, but not too tricky
of course you could do this in an arduino and use the ethernet shield to format a basic web page
- use a current cost or other independant power moniter, the cc seems to have been well hacked
or use the owl one and use rfxcom to sniff the value
- I have the excellent Brultech ECM1240 with a local sqlite database populated by the free engineG program so it would be easy to extract current power and daily totals. A further benefit is that this has 7 channels and does true NET metering so you'd know how much you export as well. Also, this fires the data to google powermeter and pachube. So an easy solution would be just to have the google power meter gadget as the whole display or do something like cycle through the daily/weekly/monthy.
I don't think there are any configurable analogue outputs on the inverter
