Just curious what will the function of these switches be?
H3c/hp pro-curve
Entrasys N7
Why is it that you are trying to mix and match switches? Are you trying to save money? I think you may be setting yourself up for trouble later if you are having an issue right now.
I just envision a situation where you get a call and all the sudden it's life or death that you get everything back up and running and your not sure what is causing your major switches not to communicate properly and half your network or more is out while you sit there stressing about compatibilities.
By no means am I suggesting that it's not a good idea to mix and match period if it means saving money. It just sounds like your heading into this without a safety net because your having issue with basic configuration between these devices.