Extension Attribute userPrincipalName // Mobile Devices // Outlook-App Configuration

Hello everybody,

i'm trying to configure Outlook for Mobile Devices. I used an Extension Attribute "userPrincipalName" to pull UPN from LDAP "Active Directory". Extension works fine in Jamf but when i put it in Outlook-App as:

<key>com.microsoft.outlook.EmailProfile.EmailUPN</key>
<string>$EXTENSIONATTRIBUTE</string

I get everything fine except for username, "@" Symobl in Username, which comes from UPN, is wirtten in Hex code

for example:

Username should be: somebody@somedomain.com

but i get in Outlook: somebody&#x40;somedomain.com (    @ replaced by &#x40;    )

How to get it without replacing? what i'm doing wrong?