In our product, "WriteVQT" is performed by EasyDAClient.WriteItem and EasyDAClient.WriteMultipleItems methods.
The "regular" writes (with just a value, no quality or timestamp) are performed by EasyDAClient.WriteItemValue and EasyDAClient.WriteMultpleItemValues methods.
Note that if you are using any of the .NET-based languages, you should rather use the QuickOPC.NET product. The methods are the same, just the parameters differ slightly.

Example (VBScript):
See IEasyDAClient.WriteItem.Main.vbs.


Rem+++
Rem This example shows how to write a value, timestamp and quality into a single item.

Option Explicit

Dim EasyDAClient: Set EasyDAClient = CreateObject("OPCLabs.EasyDAClient.5.1")
EasyDAClient.WriteItem "", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345, Now(), 192
Rem---