Extension to copy sales order fully including the pricing adjustments without freezing the price

Need help to write an extension to copy sales order fully including the pricing adjustments without freezing the price.

Currently, while copying a sales order if the "Freeze prize" check box is not checked - the Price adjustments do not copy. And if selected, everything gets copied but then in the copied order no new lines can be added as it does not retrieve the price from the pricelist(possibly because there is order price freeze)