NGUI chat window

I’am a new learner of unity3d and NGUI.

In order to create a full function chat window, I want label can show little pictures for example :[7227-\exam.png|7227]

However label in NGUI can only change the color of texts, but cannot add some ohter elements such as pictures or hyperlinks.

I tried to use a Sprite to show an image, but when calucating the position, position of this sprite is hard to location for chara has different size or other reasons which I do not figure out.

So, I want to know how to make a powerful chat window with NGUI? or can someone help me to solve this problems.

Please forgive my pool English.
Thank you.

In NGUI3.5.6 we can make a list to show the litte pictcur with key value