Problem with routes and link_to

Rails
1

I made a route
match ‘/:tasks(/:new(/:pid))’, :controller => :tasks, :action => :new
and can successfully open link http://localhost:3000/tasks/new/99
When i generate link like
<%= link_to “”, {:controller => “tasks”, :action => “new”, :pid =>
project.id } %>
it makes link like http://localhost:3000/tasks/new?pid=99
How can i make link like http://localhost:3000/tasks/new/99 ?