Magento – [Solved]Calculate incl. and excl. Vat

I don't know what i did wrong or what I'm not seeing but got the following problem I can't tackle.

I have set the show incl. and excl. vat in the shop. (Magento 1.9.0.1)
If I add a new product it tells me to place a product price.
It tells me underneath the bar [EUR] [Incl. VAT]. lets say €50,-

If I save the product Magento shows the product in the shop the prices
€50 excl vat and €60.50 incl vat?

How can I configure Magento that the price I put in is actually incl. and not excl?

Thanks MTM but here's the catch for me.. That are precise the options i have selected in my shop.
If i add a new product it tells me to give in a incl.vat price.
i did and in store the price magically changes to excl.Vat and the VAT will add up to that price.

i did repeat the same step u told me and made it excl.
Just to be sure i refreshed all of the cash. checked at my product it just tell me to put price in [euro]. and not in or ex.
I think this is in the dutch translation, but at my product page it changes the label of the input field so something must have happend when i changed the "show prices in or ex" option.

i left the price at 50 and save the product again and once again refreshed the cash.

nothing happend.. the 50 euro shows excl again (as supposed now i guess)

i got the feeling that the option show prices incl vat is just not working and the option show prices excl is always used on the shop side.