Use tinymce from tinycme package instead of the shipped one.
---- roundcube-0.1~rc2.orig/program/steps/mail/sendmail.inc 2007-11-26 11:42:36.000000000 +0100
-+++ roundcube-0.1~rc2/program/steps/mail/sendmail.inc 2007-11-26 11:44:04.000000000 +0100
-@@ -123,7 +123,7 @@
+Index: b/program/steps/mail/sendmail.inc
+===================================================================
+--- a/program/steps/mail/sendmail.inc 2009-10-14 12:52:27.000000000 +0200
++++ b/program/steps/mail/sendmail.inc 2010-07-17 17:33:23.000000000 +0200
+@@ -115,7 +115,7 @@
- // sanitize image name so resulting attachment doesn't leave images dir
- $image_name = preg_replace('/[^a-zA-Z0-9_\.\-]/i','',$image_name);
-- $img_file = INSTALL_PATH . '/' . $searchstr . $image_name;
-+ $img_file = '/usr/share/tinymce/www/plugins/emotions/img/' . $image_name;
+ // sanitize image name so resulting attachment doesn't leave images dir
+ $image_name = preg_replace('/[^a-zA-Z0-9_\.\-]/i', '', $image_name);
+- $img_file = INSTALL_PATH . '/' . $searchstr . $image_name;
++ $img_file = '/usr/share/tinymce/www/plugins/emotions/img/' . $image_name;
- if (! in_array($image_name, $included_images))
- {
+ if (! in_array($image_name, $included_images)) {
+ // add the image to the MIME message