Currently, when setting a cookie using the cookie|CO RewriteRule flag there is 
no ability to specify the path of the cookie.

'cookie|CO=NAME:VAL:domain[:lifetime]' (set cocookie)

I suggest adding a second optional parameter to specify the path of the 
cookie.  By adding it as an optional parameter, there won't be any conflicts 
with existing cookie RewriteRules.

'cookie|CO=NAME:VAL:domain[:lifetime][:path]' (set cocookie)

I've modified the add_cookie function below to work with the new path field.
=======================================================================
static void add_cookie(request_rec *r, char *s)
{
    char *var;
    char *val;
    char *domain;
    char *expires;
    char *path;

    char *tok_cntx;
    char *cookie;

    if (s) {
        var = apr_strtok(s, ":", &tok_cntx);
        val = apr_strtok(NULL, ":", &tok_cntx);
        domain = apr_strtok(NULL, ":", &tok_cntx);
        expires = apr_strtok(NULL, ":", &tok_cntx);
        path = apr_strtok(NULL, ":", &tok_cntx);

        if (var && val && domain) {
            /* FIX: use cached time similar to how logging does it */
            cookie = apr_pstrcat( r->pool,
                                  var,
                                  "=",
                                  val,
                                  "; path=",
                                  (path)? path : "/",
                                  "; domain=",
                                  domain,
                                  (expires)? "; expires=" : NULL,
                                  (expires)? ap_ht_time(r->pool,
                                                        r->request_time +
                                                        apr_time_from_sec(60 * 
atol(expires)),
                                                         "%a, %d-%b-%Y %T GMT", 
1)
                                           : NULL,
                                  NULL);


            /*
             * XXX: should we add it to err_headers_out as well ?
             * if we do we need to be careful that only ONE gets sent out
             */
            apr_table_add(r->headers_out, "Set-Cookie", cookie);
            rewritelog(r, 5, "setting cookie '%s' to '%s'", var, val);
        }
    }
}