mod_rewrite

[JonD]

OK I have a domain:

http://www.mydomain.co.uk

Now I mod rewrite so all my pages:

/index.php?p=portfolio&id=3
are written as:
/portfolio/3/

This is what I have

RewriteEngine On
RewriteBase /

RewriteRule ^about/?$			index.php?p=about
RewriteRule ^portfolio/?$		index.php?p=portfolio
RewriteRule ^portfolio/([0-9]+)/?$	index.php?p=portfolio&id=$1
RewriteRule ^cv/?$			index.php?p=cv
RewriteRule ^project/?$			index.php?p=project
RewriteRule ^photos/?$			index.php?p=photos
RewriteRule ^contact/?$			index.php?p=contact

but I want to have a subdomain called portfolio:

http://portfolio.mydomain.co.uk

but if I navigate to http://www.mydomain.co.uk/portfolio/, it automatically goes to the subdomain folder, not index.php?p=portfolio

Is there a way to stop this without having a different name of subdomain?

Thx