stale dbspace info

Hi ! Recently we had a power loss which caused a hard disk damage in turn. The disk contained several primary chunks as cooked file space for dbspaces. Although the dbspaces are lost, informix still carries the configuration infos about the now physically lost dbspaces (e.g. onstat -d lists them). On my way to reestablish this dbspaces I tried first to drop them. This was not possible, onspaces would report an "internal ISAM error". I went on recreating the dbspace files with exactly the same path as before (of course, the i-nodes will be different). This did not help much, onspaces gives me the same error as above. My question: how can I delete the stale info on dbspaces that no more exists, e.g. is there some system table to edit ? TIA, Chris