snmp would be your best bet. Here is how I am doing it with php:
$besSysHealthSrpConnectedStatexxx91;0xxx93; = snmpget(DBHOST, SNMPCOMMUNITY, "220.127.116.11.4.1.3518.104.22.168.10.1");
This will return a 1 (connected) or 0 (disconnected). If you download a free snmp browser you will see all the things that you can query. Since you are doing vb you could probably also right in some snmp traps and have it alert you when the connection goes down.
I should add that I only have one BES server so the query above is kinda hard coded for that server. If you have more then one BES server to query then you will need to mod the snmp string above.