Cannot change datagrid item background colourdynamically

[WeWeaveDean]

Hello, I am trying to change the background colour of a data grid item
dynamically.
I am using a component for each item with the item_renderer function

then in the component this is the line i am having trouble with
<mx:Canvas width="100%" height="100%" id="item_bg"
backgroundColor="{data.status_colour}">

data.status_colour is definatly set and has a hex value, #FF99CC for example

i tried
<mx:Canvas width="100%" height="100%" id="item_bg"
creationComplete="item_bg.setStyle("backgroundColo ur","{data.status_colour}")">

it did put colours on the but they were all in the wrong place, so a completed
item should be green but it is coming up with red (failed)

any ideas??

thanks