seo drupal sitemap using nodes

Hallo
this is my first post, I hope I do it properly.

I'm tring to optimize drupal for seo. I'm using clean urls with pathauto and semplified urls. To avoid duplicated content between clean urls and nodes I've disabled the spiders to visit the nodes pages by editing the robots.txt file
with
Disallow: /agenzietui/node$

Now the problem is that the sitemap module is generating a sitemap which includes all the nodes pages and not the semplified urls pages.