Position of selected text in IE6

[jcrazy2]

HI everybody,
I'm writing an application that make annotations over a HTML page.
The idea is this. User select a text, then pressing a button the HTML page put an icon over selection made.
I need to store annotation data in a database, so I need a reference to the selected text for next browsing of this page.

I'm using IE6 and I create an object TextRange through:

document.selection.createRange();

but the object text range does not support any property/method to get position of selected text.

Any suggestion?
Thanks a lot