How do you record the host name in the log file?

[ganz_friedrich]

Is there any way to record the Host name requested in the access log. (The site has many subdomains and do not want each one to have its own log file.)

I've tried this:

LogFormat "%h %l %u %t \"%r\" \"%{HTTP_HOST}\" %>s %b" commonwh

but for some reason this doesn't work. (On the other hand the %{Referer} variable works - why not %{HTTP_HOST}?).

Thank you.