Server alias without rewrite

Hello,

ISPC 2.2.33 on OpenSUSE 10.2.
There is domain www.aaa.com. I've created co-domain (server alias) www.bbb.com. Now www.bbb.com point to www.aaa.com context but rewrites domain to www.aaa.com. How to do this without rewriting?

Config:

<VirtualHost 1.1.1.1:80>
ServerName www.aaa.com:80
ServerAdmin [email protected]
DocumentRoot /srv/www/webaaa/web
ServerAlias aaa.com bbb.com www.bbb.com
Alias /stats "/srv/www/webaaa/web/webalizer"
Alias /error/ "/srv/www/webaaa/web/error/"
ErrorDocument 400 /error/invalidSyntax.html ErrorDocument 401 /error/authorizationRequired.html ErrorDocument 403 /error/forbidden.html ErrorDocument 404 /error/fileNotFound.html ErrorDocument 405 /error/methodNotAllowed.html ErrorDocument 500 /error/internalServerError.html ErrorDocument 503 /error/overloaded.html
AliasMatch ^/~([^/]+)(/(.*))? /srv/www/webaaa/user/$1/web/$3 AliasMatch ^/users/([^/]+)(/(.*))? /srv/www/webaaa/user/$1/web/$3 <IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_METHOD} ^(TRACE|TRACK)
RewriteRule .* - [F]
</IfModule>
</VirtualHost>

TIA