Product with radio option

Hy, i have a difficult question.

I'd linke to try, if, I add option with the product, and the prise show will this:
If I choose an radio option with the produtc, the price is adds for the base prise. How can I make that, just radio options will be the base price?

Sorry my bad English...

Do not put any price in the option, then it will only use the base price.

You don't understand me, i try to explain it.
If i have a product, t-shirt, the base price is 2 €.

I have S,M,L,XL,.... The S size is the 2 €, M is +0,15 €, L +0,3 €. BUT!!!
I will show this: S: 2 €, M: 2,15 €, L: 2,3 € .... but just in radio option, other option is right.

http://www.opencart.com/index.php?route ... e%20update

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