You can create an application shortcut for the slingshot manually. It should be placed to /usr/share/applications/<APPNAME>.desktop. Below is the way "SKype" shortcut looks like. Copy the contents, replace with the data that will suit your application, and voila, it should appear in the menu:

$ cat /usr/share/applications/skype.desktop
[Desktop Entry]
Name=Skype
Comment=Skype Internet Telephony
Exec=env PULSE_LATENCY_MSEC=60 skype %U
Icon=skype.png
Terminal=false
Type=Application
Encoding=UTF-8
Categories=Network;Application;
MimeType=x-scheme-handler/skype;
X-KDE-Protocols=skype

Once it is in the menu - you'll be able to pin it to the dock

You can create an application shortcut for Slingshot (the applications menu) manually. 

It should be placed in /usr/share/applications/<APPNAME>.desktop. Below is the way Skype's .desktop file looks. Copy the contents, replace with the data that will suit your application, and it should appear in the menu:

$ cat /usr/share/applications/skype.desktop
[Desktop Entry]
Name=Skype
Comment=Skype Internet Telephony
Exec=env PULSE_LATENCY_MSEC=60 skype %U
Icon=skype.png
Terminal=false
Type=Application
Encoding=UTF-8
Categories=Network;Application;
MimeType=x-scheme-handler/skype;
X-KDE-Protocols=skype

Once it is in the menu, you'll be able to pin it to the dock