[tokenyank]

Well, not using subs, I can't tell you exactly what to do, but the gateway files will allow NZD to be an option, then looking at admincp/subscriptions.php and seeing this:

	print_cells_row(array(
		$vbphrase['us_dollars'],
		$vbphrase['pounds_sterling'],
		$vbphrase['euros'],
		$vbphrase['aus_dollars'],
		$vbphrase['cad_dollars'],
		$vbphrase['subscription_length'],
		$vbphrase['recurring'],
		$vbphrase['ccbill_subid'],
		$vbphrase['twocheckout_prodid'],
		$vbphrase['options']
	), 1);
	$direction = verify_text_direction('');
	$sub['cost'][] = array();
	foreach ($sub['cost'] AS $i => $sub_occurence)
	{
		$usd = '<input type="text" class="bginput" name="sub[time][' . $i . '][cost][usd]" dir="' . $direction . '" tabindex="1" size="7" value="' . number_format($sub_occurence['cost']['usd'], 2, '.', '') . '" />';
		$gbp = '<input type="text" class="bginput" name="sub[time][' . $i . '][cost][gbp]" dir="' . $direction . '" tabindex="1" size="7" value="' . number_format($sub_occurence['cost']['gbp'], 2, '.', '') . '" />';
		$eur = '<input type="text" class="bginput" name="sub[time][' . $i . '][cost][eur]" dir="' . $direction . '" tabindex="1" size="7" value="' . number_format($sub_occurence['cost']['eur'], 2, '.', '') . '" />';
		$aud = '<input type="text" class="bginput" name="sub[time][' . $i . '][cost][aud]" dir="' . $direction . '" tabindex="1" size="7" value="' . number_format($sub_occurence['cost']['aud'], 2, '.', '') . '" />';
		$cad = '<input type="text" class="bginput" name="sub[time][' . $i . '][cost][cad]" dir="' . $direction . '" tabindex="1" size="7" value="' . number_format($sub_occurence['cost']['cad'], 2, '.', '') . '" />';
		$length = '<input type="text" class="bginput" name="sub[time][' . $i . '][length]" dir="' . $direction . '" tabindex="1" size="7" value="' . $sub_occurence['length'] . '" />';

tells me you'd have to create an NZD phrase and the html to add it to the 'table'.

That would sort out your admincp to allow NZD. No idea how that would translate to your enduser though as I have never set up subs and don't know where they parse from or anything so anything past the above would be pure speculation.