Just got Goekhan's message, try a combination of both, might be worth.
a little inelegant but I got it working by combining both ideas:
def thousands(x, pos):
'The two args are the value and tick position'
xnew = moneyfmt(Decimal(x.__str__()))
where moneyfmt is the function defined in Gokhan's link.
formatter = FuncFormatter(thousands)