Cron job using GET for XML-Sitemap

Hi,

i have installed a new install of wordpress on a domain and am using the XML-Sitemap plugin, it all seems to be working fine if i manually rebuild, but i want to schedule a rebuild once a day using the GET command with the url as indicated in the plugin.

Im using a host with cpanel and cron and usually use the Standard option.

In the text field after setting the time to run the job i have tried a couple of different things and settled on

GET http://www.domain.com/?sm_command=build&sm_key=1234567898098765443 > /dev/null

(domain name and key changed)

I get no errors that i can see but only get the html contents of my homepage emailed to me, when i check the date of the sitemap.xml page it hasnt changed.

I load the page in my browser i eventually just get a blank page but the script seems to have worked as the sitemap is update.

My question is to run this plugin as a cron job what would i need to put into the text field of the standard option in a cpanel cron job?

Have search google for various tips but using GET as i have seems closest and didnt generate any errors just fetched the homepage and emailed though.

Do i have to use curl or wget and with what options, not sure on the structure for the full string i should put in.

Domain is http://www.onyourpc.com with blog and sitemap in the root. I also use Dagon sitemap to generate a page friendly version (link in footer), this all seems to work fine with no clashes with xml-sitemap if run manually or GET link loaded in a browser.

Regards

Rob