openssl_pkcs7_encrypt and 3des

I noticed in the documentation on openssl_pkcs7_encrypt that it only uses RC2-40. I'd like to modify it to use 3DES and was wondering if anyone has already done that, and if not, where should I modify the code to enable that encoding by default? I noticed in the php 4.2.1/ext/openssl/openssl.c source that cipher = EVP_rc2_40_cbc() and that PKCS7_encrypt() uses the cipher value. Is it as simple as changing the cipher value to equal the appropriate value like 3des()? If so, what should cipher = ? I'm not a hardcore programmer, but would like to know how to scope the work to someone else than can do the work if I can't. Thanks