Selling in quantities of less than 1 unit

[Rwatking]

I have a client who sells quilting material. The product is listed in units of a square metre. How can he sell less than one whole square metre? If a customer enters say 0.5 into the quantity box in the cart, the cart rounds up the quantity to one.
All help gratefully received.

[countingsheep]

Could you not use the product attributes and have them to put in the cost for say a 1/3 metre, 1/2 metre, 3/4 metre, up to 1 metre? Then the cost would raise for raise in length?