Magento; include price attributes in (product) subtotal

Hope someone can help me with this..

I have a magento store up&running, via the attribute management ive created a price attribute (type: price, label: "Extra costs") and added it to the right attribute-set.

Now "Product A" has a price of $1 and "Extra costs" set to $2

When i order the product i kinda expect a subtotal of $3 however t开发者_开发问答he extra costs are nowhere to be found.

To clearify;

• Product A
  • Price: $1
  • Extra costs: $2
• Product B
  • Price: $2
  • Extra costs: $4

Now im ordering both products twice; i expected my cart/order overview to look like this;

• Product A | Qty: 2 | $2 (2x$1)
• Product B | Qty: 2 | $4 (2x$2)

  ---

Subtotal: $6

Extra costs: $12 (2x$2 + 2x$4)

Shipping: irrelevant

Tax: irrelevant

Total: $18

However the extra costs are not calculated.. am I overlooking something? Or is it not possible at all? (If so, whats the usage of price attributes then?)

// Roland

Attributes other than the core ones are informational only (e.g. on their own, they won't affect the price of the product). In order to get an active "extra cost" field, you would need to modify the product type definitions, something which will take much longer than you want it to.

For what reason are you including this cost outside the price? The optimal way to solve this would be to simply add it to the product price itself. Adding it to the subtotal as you've indicated will be tough (but is possible if there is a hard requirement around it). Please clarify your need a little further.