Apply a surcharge

[stonda]

Hi. I need to apply a cost port to certain products (billard table). On my site all product for which price is more than 300 euros are free transport. The price for billard table is more than 300 euros so Actinic apply a free transport. I think that the only solution is to to apply a surcharge to a product group. The product group is defined. I would like to get some help to fit the discount and surcharge settings, as it seems that I can give a discount, not a surcharge ?
Thanks

[RuralWeb]

Apply a shipping suppliment in the product details tab.

[stonda]

Thanks Malcolm. It works perfectly.

[stonda]

It works ... but I have another problem : I need to add a shipping suppliment of 150 euros. These products must be sent by road transport. So I have to create this class of transport. As this shipping suppliment is added to the port cost, I must put the value for this class at zero euro. So when the product is choosen, the suppliment is at 150 euros. But this class of transport is also possible for all the other products of the site, and I cannot prevent a client from choosing this class of transport : all customer will choose it as it is free !!!
Is it a way to propose this class of transport only for a specific category of product, and hide it for others products ?
Thanks

[stonda]

I find the solution : put a high price for this class of transport between 0 and 1000 euros (as these product are all at more than 1000 euros), and free after 1000 euros. So when the product is choosen, the port is free and we only have the shipping suppliment.