Only the second separator is shown in following configuration. Expectation would be two separators in specified locations.
<key>DesktopInfoCustomItems</key>
<array>
<string>HostName</string>
<string>SerialNumber</string>
<string>Separator</string>
<string>LastBootTime</string>
<string>StorageInfo</string>
<string>Separator</string>
<string>SupportPhone</string>
<string>SupportEmail</string>
</array>