You can change the key:
* Go to the <RTW>/data/text folder. (<RTW> means the folder you installed Rome Total War and EB in)
* Use a standard text editor (like Notepad/Word etc.) to open "descr_shortcuts.txt"
* Scroll down or search for "misc." (at the start of the line)
* There should be a line with "show_console" here, and it says "hidden" behind it. Remove "hidden" and save the file.
* If and only if you are using BI, you need to also repeat the above sequence with <RTW>/bi/data/text/descr_shortcuts.txt
* Start EB, go to controls > misc and press reset to default
* There should now be a line "show debug console" . Set to whatever key you want (cannot use any key already assigned to another function though).
This works for me at my laptop very well. MTW2 should be able to do the same, maybe you'll have to search for the preference file.

XSamatan