how to send alt-cmd-esc to "remote desktop"

There should be a button that will send the "ctrl-alt-del" command to the remote computer. This feature is used for machines with security settings requiring users to press this button combo to log in. Look for this button towards the top of the remote session in the tool bar

If you use Remote Desktop (not VNC), then I am guessing that you made a mistake in your orignal post ,and you actually want to type in ctrl-alt-del. In that case, you can press ctrl-alt-end, and that will translate into ctrl-alt-del on the remote computer.

I'm using a MAC and I don't have an "End" button. Please confirm.

Note: The Forward Delete key is located below the Help key on a full-size keyboard. Be sure not to confuse it with the Delete key located above the Return key.
For abbreviated keyboards (on portable computers), use Function-Control-Option-Command-Delete.

I've never seen a keyboard without an END key, but no matter -- you can do this using the on-screen virtual keyboard. Follow this tutorial:
http://theappleblog.com/2008/09/24/mac-101-get-an-onscreen-keyboard-in-osx/

press the Control and Command keys on the actual keyboard and the End key on the virtual one.

My last two comments are straight from Apple's Support website in regards to using Remote Desktop Connection to connect to a Windows XP machine

Thanks. I should have mentioned that I have a Spanish keyboard. There is a key with a down arrow. I guess that would be end. The delete key is right below a key called fn.

I think I've got it figuired out. thx