Anybody know how to create backlinks to this "Gästebuch" site ?

www.miriam-schwarm.de/cgi-bin/gaestebuch.cgi
www.presentcar.de/cgi-bin/gaestebuch.cgi

how to use gsa do this ?
or use other tools ?

SER should be able to post there easily out of the box. However, the two sample sites seem to have disabled the page to post new entries.