Decimal quantity in PO

2.4 Beta.

I'd like to use decimal places in a purchase order so I can purchase 1.2 meter of some thing for example.

I should elaborate that I'd like to purchase 1.2m of some inventory item.

The underlying field in the db is a double.

The form field however is
<input class='amount' type="text" name="qty" size="15" maxlength="15" dec="0" value="1">

No decimal places.
Can this be altered ?

The field is correct for a free entry (non inventory item).

Many thanks.