Params from %amp; spererated url not coming through to the controller


I am using fusion charts and passing a data_url. The data_url param
are linked with the normal & character. However, the flash object url
encodes the data_url before calling it, so my rails app is hit with

Rails seems to through the params out the window when confronted by the
%amp; enstead of &.

How would you go about extracting params when they are seperated by
url_encoded params, instead fo the usual & seperator.