We suggest you split the task in two stages:
1. Implement your scenario without using a tooltip. Use an UpdatePanel or RadAjaxPanel on the page, with your controls inside, make it work as expected. In case you use RadAjax, the following example might be useful:
2. Place your UpdatePanel inside a RadToolTip (e.g. between the tooltip's opening and closing tags).
One example, using a regular asp:UpdatePanel can be found here:
In case the update panel in the tooltip does not work as expected, please open a support ticket and send us your project, and we will make the necessary changes for you.
the Telerik team