Global XSS filtering bypass

[eluser]Anestetikas[/eluser]
Hi,
I use the global xss filtering for my codeigniter projects, but for one particular textarea I need to use rich text editor. So could somebody explain me how can I bypass global filtering for only one field.

I have found some topics on this subject, but all of those were suggesting to alter system files, witch is not what I want to do.