Ordering Shippment Methods.

I've noticed that the shippment method selected for an order is set to the cheapest, which is fine except I want to offer customer a discount ( negative shippment cost ) if they opt to collect in store.

The rational is that we want to help drive people instore presenting more options to up sell + by bringing people instor I can reduce my shipping costs.

thanks in advance

in the shipment window you can click and drag them into position in admin

Thanks John but do you know how one becomes the default, my issues is the default selection is always the cheapest and -ive values are always checked

Folks, wondering if anybody had any thoughts on this, I'm assuming this is going to be a chnage to the query or logic that excludes -ive values from the default selection but do not have a clue where to start looking.