pkcs7_sign problem

Hi, I am already using some of the openssl functions and are working ok. Up to now, I am using openssl_seal and openssl_open to pass encripted data through forms (if anoybody needs help with that pls tell me, I had to use base64_encode/decode functions to convert non printable characters generated with openssl functions). Now I need to send signed messages, I wanted to use pkcs7 functions but when I try to sign the message I find this error openssl_pkcs7_sign(): error getting private key I am using the same public/private keys that I used for openssl_seal/open. I think there's the problem, but I don't know what to do in order to get a valid certificate... Thanks in advance, Franco Galian lists@lhs.com.ar PD: I'm using apache 1.3.19, php 4.0.6 on OpenBSD 2.8