button_to with "GET" and extra parameters

I have the following in one of my views:

     <%= button_to 'Edit', {:action => 'edit_mbr_cit', :id =>
@member, :extra => @citation}, :method => 'get'%>

This generates resaonable HTML as follows:
<form method="get" action="/gateaccess/edit_mbr_cit/7641?extra=11"
class="button-to"><div><input type="submit" value="Edit" /></div></

However, when clicked, the "GET" request does not have the "extra"
parameter, as shown below:

Processing GateaccessController#edit_mbr_cit (for at
2007-07-14 11:12:51) [GET]
  Session ID: e1d723aad01fa7332de579a7bd15f59e
  Parameters: {"action"=>"edit_mbr_cit", "id"=>"7641",

Can somebody explain why the controller isn't receiving what the HTML
says it should be generating?