style data being stripped out from CKeditor?

greetings!

i have recently installed CKeditor in ELGG (www.elgg.org) and found that although the editor passes the message values to the site code/db ok.. the CSS tags are being stripped out of the message somewhere within the processing.

i've explored the elgg code to see if i can find why this is.. and haven't found anything, so i'm wondering whether there may be something that someone here can point me to look at?

additionally, i have found that an image i have uploaded to my test site via CKeditor is visible for me (even when i'm not logged in to the site) - but isn't visible for a friend who has looked on a different pc in a different location.

for reference, i have installed the latest version of CK editor and am using the plugin for CKeditor that is available in the elgg community here: http://community.elgg.org/pg/plugins/release/411930/developer/springs/ckeditor-replaces-tinymce

anyone?
thanks