Variable prices not being passed through node_checkout

I'm trying to use a combination of varprice and node_checkout to sell event tickets by donation. Unfortunately the price that is entered in the cart is always the default value for varprice, rather than the price entered by the user. It seems that the price submitted into varprice is being lost by node_checkout. I am trying to dig through the code for both modules to figure out how to get it to work, but I'm a bit lost. If you have any suggestions on how to get it working then hopefully I can put together a patch for one or both modules to get them to work together. Thanks!