I just recently purchased the HCS Voice Packs and am having a blast with them. I have noticed that the keybinds are all set for a UK keyboard, which has a few differences over the US/Canadian counterparts. Most of the default key binds will work without modification as listed here ..
http://forum.hcsvoicepacks.com/forum/te ... t-keybinds
However, if you want to use voice attack with Shield Cells, then the default key mapping will not work on the US keyboard. The HCS packs don't use the SHIFT key for anything. Thankfully, it's not a difficult problem to solve.
SOLUTION: Instead of using the # key (which on a US Kb is given by pressing SHIFT-3), use the ' - single quote key (located next to the Return/Enter key). You will need to change this in the games default key bindings. In this way, you can use the HCS Voice Packs default settings without changing them.
Hope this helps!