John - For Alex this time

I got some anwsers on my questions but it is not complete and i need the expert answer.
What i basically need to do is Stock Quote blinking grid.

I tried to use the XMLTable to load the initial values.

But i got stuck when trying via HTTPRequest to update this XMLTable partially with changes values (like the ask price but the row stays). I was only able to replace the existing XML wich is not what i'm tryin to achieve.

Also i was unable(still with XMLTable) to acced a cell via the Rowid and the col.
Eventually, is it possible to dynamically adda and remove lines based on the unique ID of the row.

Is the grid suitable for that ?
What's the way for that ?
Thanks
John