TinyMCE. Insert text into the TinyMCE textbox at the current cursor position.

Hi,
I'm using TinyMCE in my ASP.NET application. Got it working in an updatepanel by using TinyMCETextBoxExtender. All good, however ...
This might be a silly question but what is the best way to stuff text into the TinyMCE textbox? Let me please explain:
I have got a number of buttons outside the TinyMCE textbox which when clicked display a modalpopup and allow the user to select stuff (I won't bore you with what the stuff is but I need this on the .NET side since it hooks into the database etc) the result is a string of characters, e.g. {IMAGE=BOAT}, which then needs to be pumped into the TinyMCE text box at the current cursor position. Outside of TinyMCE this string does something useful! Any thoughts please on how this might be done?

Any help / pointers would be greatly received since I have been pulling my hair out recently!

Thanks.

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