Using validators on custom controls

[shodson]

I know how to use validators on the <asp:___> server controls.

Now I have created my own server controls. How can I use the standard
ASP.NET validator controls to validate my custom control? For example,
if I have a RequiredFieldValidator, and I want to set it's
ControlToValidate property to one of my custom controls, how can they
be tied together? How does the RequiredFieldValidator know how to
validate my custom control?