It took me ages to actually figure out how to do this.
Quick way is to click the link box up on top of the post and enter in the 'A' font box, your url and
it will look like this (ignore the _ it is not meant to a space either )
[url_=www.XXXXXX] words want to hyperlink [/_url]
to hyperlink an image (i have to double check this)
[url_=www.XXXXXX] [img_]image code [/_img] [/_url]
Hope this helps.