Not so safe: Split the mains cable from your Soladin just before the plug. Remove enough of the outer sheath to expose the Live - put the clamp around this. No need to remove insulation from Live!!!
Also may affect your warranty; but you can do it to a short extension lead instead. Quite useful around the house if you don't have an IAM. They still have not arrived in Aus!!
If you want to do 'maths' and add/subtract values, as Automan suggests, the lack of any negative values prevents you getting a net total. For that, you need a home grown solution like open energy monitor, which detects the phase (i.e positive or negative, import or export).
PVoutput does the math automatically so long as you can identify generation separately from comsumption. See the net output from my bridge http://www.pvoutput.org/intraday.jsp?id ... 3&da=1&s=1
@Automan What's happened to you solar generation? it seems way down on last year.