Hello, Otto
I'm sorry, but we don't have a VBA programmer in our office. Therefore I've searched in Google. Please, look here:
http://support.microsoft.com/kb/189498 (INFO: How to Use DDE in Visual Basic to Communicate with Other Windows Programs)
For example, LinkTopic in Excel is:
asdlog|ddesrv!srviDATA_PACKET
The article above shows that you can use the "LinkNotify" event in your code.