rewrite tolower

[BBonanza]

I have this rewrite rule working fine

RewriteRule ^used/([^/]+)/cars/?$ used/mks.asp?used=$1 [NC,NE,L]

I tried putting this tolower rule in but it doesn't work.

RewriteMap lower int:tolower
RewriteRule ^used/([^/]+)/cars/?$ used/mks.asp?used=${lower:$1} [NC,NE,L]

I have tried several different variations but still no luck - can it be done?

Thanks guys

[Caterham]

I tried putting this tolower rule in but it doesn't work.

The RewriteMap must be defined in your httpd.conf (per-server context).