Minimum Amount for Free Shipment

[gojeta]

I have Joomla 2.5.8 and VM 2.0.14

I tryed to find an answer in forums with the search function without luck.
If someone else find a topic with an answer please provide it.
I have the following problem.

In Shop - Shipping Methods i want to use Minimum amount for free shipment field for a price without vat.
My problem is that the price in the field works with 2 differend ways, one with no vat and one with vat.
What i mean is this:
We have 2 persons no1 gets no vat and orders 300 so he gets correctly the free shipping.
Now no2 who has vat, orders 250euro but with vat gets above 300 so he will get free shipping while he souldnt as his orders are 250 and not 300.
Is there a way to make free shipping field check always the base price and not the final price incuding vat or taxes etc?

Thanks in advance,

Iraklis