Thanks for the replies, ... hm, is there a complete description of ASN.1 formmat available? thanks, Arne -- Arne Mueller Biomolecular Modelling Laboratory Imperial Cancer Research Fund 44 Lincoln's Inn Fields London WC2A 3PX, U.K. phone : +44-(0)171 2693405 | fax :+44-(0)171-269-3534 email : a.mueller at icrf.icnet.uk | http://www.icnet.uk/bmm/