Unable to retrieve singleValueExtendedProperties of an itemattachment

Question

I have an email message which has another email message as an item attachment.

I am trying to read the singleValueExtendedProperties of the attached email message using below query, but it doesn't work.

I don't see singleValueExtendedProperties in the response.

https://graph.microsoft.com/v1.0/users/{mailbox}/mailFolders/Inbox/messages/
{messageId}/attachments/{attachmentId}?$expand=microsoft.graph.itemattachment/
item($expand=microsoft.graph.message/singleValueExtendedProperties(
$filter = id eq 'string 0x001A'))

Answer 1

I am also trying to read singleValueExtendedProperties for an attachment which is inside a email, is that possible not ? not allowed by design?