No name when calling from SIP to H.323 extension.

[ACISD]

Hi,
we have recently installed MES for one of our client,
Also did integration with their
old CM <h.323 trunk>to new CM(MES)<sip trunk> to SM(MES).
H323 phones are registered on their old CM.
SIP phones are registered on session manager(MES).
When calling from h.323 to SIP we can see name on h.323 phone display.
But when calling from SIP to H323 extension there is no name on phone display.
Could anyone advice if this is possible & if yes how can we achieve this.

Thanks in advance.