I've made some changes to rexxcurl.c (version 1.4) to make ftp with ssl work.
The main changes are the RXCURLOPT_FTPSSLxxx types are changed to RXCURLOPT_BITMAP_AUTH - is this correct?
I also had to comment out the SOURCExxxx section as this caused the compile to fail (curl 7.17.1).
Finally I changed the sprintf format specifiers for the progess callback to use %.0f as I think the actual value should never include a fraction.
Also please note that the sftp:// and scp:// libssh2 url format work fine.