Magento 1.5-1.8 – Handling Two Tax Rates with Same Percent but Different Names

I'm struggeling with this for a few days now.

I'm trying to sell products and insurances. Products have 19% VAT, insurances have 19% insurance tax.

I added a new Tax class, rate and rule.

If I see this correct, magento aggregates taxes with the same rate. There is no way to prevent this (at least I didn't found one)

\Mage_Tax_Model_Sales_Total_Quote_Tax::_totalBaseCalculation()

It doesn't matter what priority my rules has.

I'm ending with this, which is correct calculated, but not splitted in the correct parts:

MwSt. (19%)      21,70 $
Vst. (19%)       21,70 $
Tax              21,70 $

After adding shipping, it looks like this, now the sums are totally screwed:

MwSt. (19%)      22,50 $
Vst. (19%)       21,70 $
Tax              22,50 $

The interessting part is, the invoice in the backend is again ok (the pdf too):

Shipping & Handling Tax   0,80 $
MwSt. (19%)              15,97 $
Vst. (19%)                5,73 $
Total Tax                22,50 $

At the moment I think magento can't handle two different taxes with the same percent rate. At first glance, this use case isn't needed, but this evaluation is wrong :-/

Any ideas on this?