SAVF restore problem

Hello,
we are trying to save and restore a library made of 2 *PGM, 1 *SRVPGM and
a *FILE.
The SAVF has been created on a V7R1 (and it is a virtual system) but should
be deployed on a V5R4.
The programs have been built for V5R4 using the TGTRLS(V5R4M0) option:
there are 1 CLLE *PGM, 1 CLE *PGM and 1 CLE *SRVPGM (we need the server
program since we need to create some stored procedures associated to the
program)
The command used to save the library is

SAVLIB LIB(MYLIB)
DEV(*SAVF)
SAVF(SAVFLIB/MYSAVF)
TGTRLS(V5R4M0)

The SAVF is then deployed on a V5R4 and it fails to restore the *PGM and
*SRVPGM objects. The restore is performed by a remote partner, so we do not
have the control about that. They report some errors. The command used is

RSTLIB SAVLIB(MYLIB) DEV(*SAVF) SAVF(SAVFLIB/MYSAVF) MBROPT(*ALL)
ALWOBJDIF(*ALL) RSTLIB(MYLIBNEW)

The errors are CPF3773 or CPF3770 if they use RSTOBJ:

Message ID:.... CPF3770 Severity:........ 30
Message Type:.. Diagnosis
Submit date:...... 16/07/19 transmission time:...... 13:58:35
message:
Not save or restore object for the library DBMOTOLIB.
Cause:
There is no save or restore object for the library DBMOTOLIB

The result is that the *PGM and *SRVPGM objects are not restored - but the
library and the *FILE are restored.
The target system is a Japanese one, but in previous scenarios with
different programs and SAVFs created on a V5R4 the restore was working fine
on this system.

If we try to restore the same SAVF on a V7R1 it works fine and all the
objects are restored correctly.

Is there any issue related to such gap between the system used to create
the SAVF and the actual target system? Or the fact that we have used a
virtual system can be an issue?

Thanks
Alberto