Replacement Sonus Faber grille strings?

Hi guys, the grille and stand strings on my Sonus Faber Guaneri Evolution speakers are beginning to sag.  While I know its a straight forward task to retension the grille strings, I am just thinking that at some point I will need to replace the strings. The stand strings look a bit more difficult as it will require me to dismantle the stand.  

Of course I have no intention of paying the ridiculous prices SF wants to charge me.  So does anyone know of a source for the string?