I guess you don't "see" the subroutine because Net::SSLeay uses autoloading for many of its subroutines. So what you can do is trigger the autoloading by calling the sub, and the set the break the normal way. Here's an example for Net::SSLeay::open_tcp_connection:

  DB<1> use Net::SSLeay

  DB<2>  b Net::SSLeay::open_tcp_connection
Subroutine Net::SSLeay::open_tcp_connection not found.
  DB<3> x Net::SSLeay::open_tcp_connection()
0  0
1  '-e 743: open_tcp_connection: destination host not found: `\' (port
+ ) ()
'
  DB<4>  b Net::SSLeay::open_tcp_connection
  DB<5>
[download]

So, the second attempt to set the breakpoint works. You might want to consult the sub's documentation for the (unlikely) case that calling it has unwanted side effects.