Wordpress plugin - Flashvars field not saving?

Hey guys.

I'm using the jwplayer wordpress plugin, and trying to enable pseudostreaming in the player.

I go into the advanced settings for the custom player I'm using, and try entering this into the flashvars textbox:

provider:'http', 'http.startparam':'starttime'

However, when I click save and go back to the page the box is empty again! I've also tested with other text but nothing seems to be saving in the field, it is always blank when I return to it.

Any help?

Thanks!