You don't need to use XML files. Look at the SmartFolders *SyncConfig* section. If you enable SmartFolders then the affected user(s) (or you) can add the sync config directive folders.
So at the top level of the folder tree, you would add
*SyncConfig*
and as a child folder add
sendasname&Whatever name
Whatever name can be an encoded version of the user's name such that it will display properly on all email systems.
From the notes
* User control of Mobile Sender Name
* ----------------------------------
* In case the user's display name contains non-ascii characters, and it gets corrupted
* when sending emails from the device, a sendasname directive can be used to provide a
* MIME-encoded Sender Name to be used by the backend.
*
* To get the correctly formatted name, send yourself an email through the web
* client, and then right-click on the received email and Show Original. Look for
* the From: header and copy the name from there. Don't include the email address
* part - or any surrounding "" marks. Note that the encoding zimbra uses will most
* likely be utf-8 rather than ISO-8859-1 as seen in the following example
*
* For example
* =?ISO-8859-1?Q?Andr=E9?= Pirard
* The example above is taken from the rfc2047 document, and appears in a CC:
* CC: =?ISO-8859-1?Q?Andr=E9?= Pirard <PIRARD@vm1.ulg.ac.be>
* For reference:
RFC 2047 - MIME (Multipurpose Internet Mail Extensions) Part Thr (RFC2047)
So, for this example you would have folders named
*SyncConfig*
sendasname&=?ISO-8859-1?Q?Andr=E9?= Pirard
with *SyncConfig* being a top level folder, and the other being a child folder of the *SyncConfig* folder.
Edit: For your name from your previous post you would use
*SyncConfig*
sendasname&=?utf-8?Q?F=C3=A1bio?= Viero Interop IT Consulting