Please see this article from BestCrypt online help:
Besides of the commands listed in this article, there are three other options:
1. BestCrypt allows to mount container and enter password in the command-line prompt, but the function is not documented. We do not recommend to enter password in such a way, because we believe that in many cases it may become a security leak. If you believe that your way of using the feature won't cause security problems, you can enter password in the following way:
>BestCrypt.exe Open C:\container.jbc X: -p:=password=-p
2. Mount from remote key block file (.kbb).
BestCrypt.exe open <ContainerName> [mountpoint] [-KB <keyblockfilename>]
> BestCrypt.exe open C:\folder\container/jbc G: -KB C:\folder\keyfile.kbb
3. Mount a container encrypted with password and a key file. Use -KF flag to specify the key file name (with full path):
BestCrypt.exe open <ContainerName> [mountpoint] [-KF <keyfilename>]
> BestCrypt.exe open C:\folder\container/jbc G: -KF C:\folder\keyfile.jpg
These options can be used together.
Sample of the whole command line:
>BestCrypt.exe open C:\container\testContainer.jbc E: -KB G:\keyblock\testContainer.kbb -p:=123456789=-p