Problem with accessKey value same letter with lower and upper case

problem with accessKey attribute value p (lowercase) and P(uppercase) for different html buttons…
the browser unable to differentiate between upper and lowercase key …

i have a simple form with two buttons, and i want to trigger these buttons with keyboard keys in combination with Alt key.
for example Alt + P (uppercase) should trigger button 1 and
Alt + p (lowercase) should trigger button 2

Browser: IE 8.0

here is the code…

<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN” “”>
<title> Alt KeyStrokes </title>
<form method=“post” action=“”>
<button onclick=“alert(‘Big P’);” accesskey=“P” >Button1(<u>P</u>)</button>

<button onclick=“alert(‘Small P’);” accesskey=“p” >Button2(<u>p</u>)</button>


here the behavior is strange, when i press Alt+P in keyboard, button1 is triggered and when i press Alt+Shift+P in keyboard, button2 is triggered …how to overcome this problem…

need suggestions

Alt + Shift + p (for uppercase p) should trigger button 1