When you install Civil 3D 2013, you have to expand the accordian to get access to install the following Sub-Components:
- Autodesk Storm & Sanitary Analysis 2013
- Autodesk Subassembly Composer for AutoCAD Civil 2013

If you create a deployment and you do not select those components, you will NOT be able to add it in the deployment afterwards if you try to Create & modify a deployment [in the Tools folder].

Fear not, if you have already installed Civil 3D 2013 without these options, you can manually install it on the target computers by copying the Sub-Components from the DVD and installing it a la carte. It is located in the following folder:
AutoCAD_Civil3D_2013_English_Win_64bit\x64\Components
Thanks to Christian Barrett for confirming that this workaround actually works...
Epilogue
Only SAC2013 can be installed in this method. I am investigating if SSA 2013 can be installed this way.
Epilogue II
To solve this problem, run the setup of AutoCAD Civil 3D again. It should will alert you that AutoCAD Civil 3D is installed. Just expand the accordian to install the 2 sub-components.


Thanks to Avto Chachava for this workaround.