Get data from system clipboard

Hi friends,
Now i am going to get some data from system clipboard, probably strings/TDes, and not using controls like EDWIN or something else.
I have seen the sdk about clipboard, its main meaning is getting a stream id by
[code]
TStreamId stid = (cb->StreamDictionary()).At(KExampleClipUid);
[/code]
where cb is created by
[code]
cb=CClipboard::NewForReadingL(fsSession);
[/code]

very curious, it seems any data in clipboard is stored by a pair of UID and StreamID, thats understandable that the system has to find a specific data entry by its UID, but how can i get the data by the UID[in the example above, how can i know which uid i am finding?], the example Symbian gave us is to copy a custom data into system clipboard with a custom UID, and then paste it out with the same UID. Thats not what i want.

Now what i wanna do is to get the string that is copied to clipboard already, just like the user copied a string to clipboard in SMS editor, and then i can get that in my application.

I would be so appreciated if someone help :)
Thanks in advance.
kcome