stupid little problem: turtle+firefox?

Since I run Firefox 11 (on Mac Lion) whenever I get a turtle file (ie text/turtle) the browser insists in downloading the result and run an external program to display it, instead of displaying the text in the browser window. Does anybody know how to set this or has anybody an extension to firefox to display text/turtle directly (I did find such an extension for JSON, for example)?

Thanks

Ivan

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Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf