In outlook 2010 when you try to reply to a message that
you have received and if it contains an attachment you will not be able to
reply with the attachment the attachment get dropped.
I found two ways to achieve this
1. You can download a plugin and once you installed it
will give you button call “Custom Actions” with that you get an option call
“reply all with attachments”. If you want to reply to only one you’ll have to
drop the rest
Here is the link to download - http://replyallwithattach.codeplex.com/
2. Step to is already with outlook but it might confuse
the receiver,
- Go to File>option>
select “Mail” from the left side and under
“Replies and Forward” you will see an option call "when replying to
a message", from that select the option call “attach original
message”
When you open the message with the attachment that you
want to reply will see the whole message has been attached as an attachment
like below
Once you open the attachment you will see the original
attachment as in the below image.