It's most likely defined as string becuuse it's the lowest common denominator. You can convert everything to string.
Do you really need to send both elements of the cluster seperately? Can't you just send the cluster as "adapt to type"?
Please bear in mind, I'm not an expert in LabVIEW DLL programming, so what I'm posting may be incorrect.....
Shane.
Using LV 6.1 and 8.2.1 on W2k (SP4) and WXP (SP2)