Callsign for a former charter company of Switzerland (Balair)

How can I request a callsign for BALAIR, a former charter airline in Switzerland. Their callsign was BBB which belongs now to WESTJET. Before I went to Swissair I worked for Balair and I have an FBW A320NX installed. Is this eventually possible?
Thankyou in advance for an answer. Regards Jörg Trefzer