We currently do not support NT LAN Manager (NTLM) on the server-side with the Kemp Edge Security Pack (ESP) feature.
NTLM is a connection-oriented security protocol. It only secures the connection between the LoadMaster and the client, and not between the LoadMaster and the server. Because NTLM does not transmit the password to the LoadMaster (it only transmits a hash) this cannot be used to fill a form for Basic or Forms-Based Authentication to the server. Only the Active Directory (AD) would be able to decipher the Password Hash to validate it. With ESP enabled, the Real Server would not receive the initial requests. Instead, it is all handled by the LoadMaster.