I suggest you to study the examples that are installed with NI-DAQ: you'll find them in \samoles\daq\AO. All the projects that start with the WFM prefix can help you (WFM stands for Waveform Generation). For example, WFMsingleBufRegenerate.prj explains how to output continuously a sinusoid or a sawtooth wave.
This example can be extended to fit your requirements adding controls for frequency, amplitute and # of cycles and making parametric the buffer generation function.