[imp] horde-webmail-1.1.3 - Enable pgp in DIMP - already wotking in IMP

[A]

I have horde-webmail-1.1.3 working well on my server. PGP encryption  
is enabled and functioning when using IMP. I am using a default  
install with no special directories, etc.

When I switch to DIMP, there are no options for encryption in the  
interface and I am unable to find any settings to enable the  
functionality within DIMP.

How can I utilize the encryption when using DIMP? I prefer using the  
DIMP interface.