[VB2010] Find PROMPT position

My goal is to check if in a EXTERNAL window is blinking the prompt (ready to enter letters from keyboard) and its position.

Normally the external window never displays a prompt... is displayed a prompt only when you have to login.

I can't enumerate the childs, searching a textbox, because are CUSTOM controls (Spy++ only find the Main Window, not other childs)

I don't find any API that verify if a PROMPT (prompt, not the mouse cursor) is active on the screen and gets its position.

Any help?

Ty :)