I would have thought that Half-life uses the Windows keyboard drivers to take input from the keyboard. If thats so would you not just change your settings to tell Windows that you want to use the standard Spanish keyboard layout? Do you have to to the "Shift"+"-" to write the "?" symbol when you are using a program like Internet Explorer or MS Word, or does this just happen in ESF?
HL uses the US keyboard configuration ingame. Although STEAM can use Windows configuration. Thats why you can type normaly in the console cause that is STEAMS part. But if you want to use keys ingame you nead the US values for them.