I don't know if it's necessary, but the 3 dlls I have are libssl32.dll, libeay32.dll, ssleay32.dll.
Did you try doing this:
If that doesn't work, try copying the 3 dlls into the \windows\system32 dir? Then restart mIRC and try connecting as above again.
Are you sure you are using mIRC 6.16? Try typing
//echo -a v: $version ssl: $sslready If it echos
v: 6.16 ssl: $true, then your dlls are installed and ready.
-genius_at_work