You would normally have a better chance of getting this type of general DAQ question answered by posting it under "Measurement Devices>>Multifunction I/O"; however, since I happen to know the answer, here goes:
To perform analog output starting from a digital trigger, you simply need to call AO Config, AO Trigger Config, AO Start, etc (see example that ships with LabVIEW). Execution will not suspend on AO Start; in fact, execution should not be suspended with analog output unless you call AO Wait. The reason AO Wait is called in our examples is to prevent AO Clear from being called before AO generation is complete. AO Wait is asynchronous, which means it will allow your VI to perform other parallel tasks, even if execution seems to have stopped on AO Wait. You should
notice that AO Wait is merely a timed While Loop.
Alternatively, you can implement your own wait mechanism with Wait Until Next ms Multiple function to wait for the generation to complete.