Что-то я запутался...
Код:

[PS] C:\Windows\system32>Get-ExchangeCertificate -Server MAIL | fl
AccessRules :
CertificateDomains : {MAIL.*.net}
HasPrivateKey : True
IsSelfSigned : False
Issuer : CN=dns-SERVER-CA, DC=*, DC=*, DC=net
NotAfter : 02.10.2016 3:51:30
NotBefore : 03.10.2015 3:51:30
PublicKeySize : 2048
RootCAType : Enterprise
SerialNumber : 7D00000004A0ACC62675FF272A000000000004
Services : IMAP, POP, SMTP
Status : Valid
Subject : CN=MAIL.*.net
Thumbprint : 2B5251AECCFC03D17A33371968417D868CFE2FB5
AccessRules :
CertificateDomains : {MAIL, MAIL.*.net}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=MAIL
NotAfter : 03.09.2020 19:53:19
NotBefore : 03.09.2015 19:53:19
PublicKeySize : 2048
RootCAType : None
SerialNumber : 59B87B728F9D20AD41A3807D7F08C534
Services : IMAP, POP, SMTP
Status : Valid
Subject : CN=MAIL
Thumbprint : DF0792D3A570FD38046ECF2308465C1928096450
AccessRules :
CertificateDomains : {}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=Microsoft Exchange Server Auth Certificate
NotAfter : 19.10.2019 0:18:05
NotBefore : 14.11.2014 0:18:05
PublicKeySize : 2048
RootCAType : None
SerialNumber : 1C91764D84BC97BF41CFE10616B65B4A
Services : SMTP
Status : Valid
Subject : CN=Microsoft Exchange Server Auth Certificate
Thumbprint : 4BAF4C25E6F37B3DB9CF518C885A1DA3802A0CE7
AccessRules :
CertificateDomains : {MAIL, MAIL.*.net}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=MAIL
NotAfter : 14.11.2019 0:14:49
NotBefore : 14.11.2014 0:14:49
PublicKeySize : 2048
RootCAType : None
SerialNumber : 16481FD21BB0309A45BFBE8D1E719D52
Services : IMAP, POP, SMTP
Status : Valid
Subject : CN=MAIL
Thumbprint : 7496F1D31DCAFB774121B8837854C3FEB8552CA5
AccessRules :
CertificateDomains : {WMSvc-MAIL}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=WMSvc-MAIL
NotAfter : 10.11.2024 22:06:42
NotBefore : 13.11.2014 22:06:42
PublicKeySize : 2048
RootCAType : Registry
SerialNumber : 373612A53F22F29A47AD9C57331FB246
Services : None
Status : Valid
Subject : CN=WMSvc-MAIL
Thumbprint : C4E9FCBCF598B432B4E51A0C4CC6ACDDF52D2694
А какой нужно выбрать?)
Вот этот же?
2B5251AECCFC03D17A33371968417D868CFE2FB5