alignment in tinymce editor in compose page in roundcube

[behnaz]

Hi,
I have a problem with alignment in tinymce editor in compose page in roundcube webmail!!!!!!
My problem is that "mce_justifyleft///mce_justifyright///mce_justify" don't work in "FireFox" and "IE"

so can someone  help me, and guide me !!
What do I do that it works, correctly???

please,help me.

thanks a lot.