--- httpd-2.0/modules/mappers/mod_vhost_alias.c	2004-05-30 00:18:19.000000000 +0200
+++ httpd-2.0/modules/mappers/mod_vhost_alias.c	2004-05-30 00:24:36.000000000 +0200
@@ -64,6 +64,8 @@
 typedef struct mva_sconf_t {
     const char *doc_root;
     const char *cgi_root;
+    const char *unset_part;
+    int unset_part_len;
     mva_mode_e doc_root_mode;
     mva_mode_e cgi_root_mode;
 } mva_sconf_t;
@@ -75,6 +77,8 @@
     conf = (mva_sconf_t *) apr_pcalloc(p, sizeof(mva_sconf_t));
     conf->doc_root = NULL;
     conf->cgi_root = NULL;
+    conf->unset_part = "_";
+    conf->unset_part_len = 1;
     conf->doc_root_mode = VHOST_ALIAS_UNSET;
     conf->cgi_root_mode = VHOST_ALIAS_UNSET;
     return conf;
@@ -103,6 +107,14 @@
 	conf->cgi_root_mode = child->cgi_root_mode;
 	conf->cgi_root = child->cgi_root;
     }
+    if (strcmp(child->unset_part, "_") != 0) {
+        conf->unset_part = child->unset_part;
+        conf->unset_part_len = child->unset_part_len;
+    }
+    else {
+        conf->unset_part = parent->unset_part;
+        conf->unset_part_len = parent->unset_part_len;
+    }
     return conf;
 }
 
@@ -211,6 +223,17 @@
     return NULL;
 }
 
+static const char *vhost_alias_set_part(cmd_parms *cmd, void *dummy,
+					const char *unset_part)
+{
+    mva_sconf_t *conf;
+    conf = (mva_sconf_t *) ap_get_module_config(cmd->server->module_config,
+						&vhost_alias_module);
+    conf->unset_part = unset_part;
+    conf->unset_part_len = strlen(unset_part);
+    return NULL;
+}
+
 static const command_rec mva_commands[] =
 {
     AP_INIT_TAKE1("VirtualScriptAlias", vhost_alias_set, 
@@ -225,6 +248,9 @@
     AP_INIT_TAKE1("VirtualDocumentRootIP", vhost_alias_set, 
                   &vhost_alias_set_doc_root_ip, RSRC_CONF, 
                   "how to create the DocumentRoot based on the host"),
+    AP_INIT_TAKE1("VirtualUnsetPart", vhost_alias_set_part,
+                  NULL, RSRC_CONF,
+                  "how to set the replacement for empty parts"),
     { NULL }
 };
 
@@ -249,8 +275,9 @@
     }
 }
 
-static void vhost_alias_interpolate(request_rec *r, const char *name,
-				    const char *map, const char *uri)
+static void vhost_alias_interpolate(request_rec *r, mva_sconf_t *conf,
+				    const char *name, const char *map,
+				    const char *uri)
 {
     /* 0..9 9..0 */
     enum { MAXDOTS = 19 };
@@ -326,8 +353,8 @@
 	end = dots[ndots]; /* ptr to the character after the last one */
 	if (N != 0) {
 	    if (N > ndots) {
-		start = "_";
-		end = start+1;
+		start = conf->unset_part;
+		end = start+conf->unset_part_len;
 	    }
 	    else if (!Nd) {
 		start = dots[N-1]+1;
@@ -344,8 +371,8 @@
 	}
 	if (M != 0) {
 	    if (M > end - start) {
-		start = "_";
-		end = start+1;
+		start = conf->unset_part;
+		end = start+conf->unset_part_len;
 	    }
 	    else if (!Md) {
 		start = start+M-1;
@@ -425,7 +452,7 @@
      * canonical_path buffer.
      */
     r->canonical_filename = "";
-    vhost_alias_interpolate(r, name, map, uri);
+    vhost_alias_interpolate(r, conf, name, map, uri);
 
     if (cgi) {
 	/* see is_scriptaliased() in mod_cgi */