different colour codes in different browsers

Hello,

i'm using FCKEditor version 2.6.4, in a RT (Request Tracker) version 3.8.8,

When i edit my text with IE8, FCK Editor generates the following code :

<span style="color: #ff0000">ROUGE<br />
</span><strong><span style="color: #ff0000">ROUGE&nbsp;GRAS<br />
</span></strong><span style="color: #00ff00">VERT<br />
</span><em><span style="color: #00ff00">VERT&nbsp;ITALIQUE</span></em>

When i edit my text with Firefox4, FCK Editor generates the following code :

<span style="color: rgb(255, 0, 0);">ROUGE<br />
</span><strong><span style="color: rgb(255, 0, 0);">ROUGE&nbsp;GRAS</span></strong><br />
<span style="color: rgb(0, 255, 0);">VERT<br />
</span><em><span style="color: rgb(0, 255, 0);">VERT&nbsp;ITALIQUE</span></em><br />

the difference is on the color coding hexa/vs/rgb

the problem is the RT system doesn't interpret the colors coded in hexa.

So i want to know if there is some option in FCK config to have rgb generated code when using IE ?

thanks for any help
raphaël