I was hunting around for some VAR code so I don't have to write my own; I find the following.
http://waynecain.blogspot.com/2011/03/impulse-response-function-in-stata.html
The first link takes you to the download page for some Matlab code. There's a example.m showing how things work.
The second link describe how you can run VAR using the build in Stata functions. The page is worth a read, but it summarize to doing the following:
tsset dates
varsoc var1 var2 var3, maxlag(12)
/* to test model lag to use */
var var1 var2 var3, lags(1/3)
/* estiamte */
irf create order1, step(12) set(myirf1)
irf graph oirf, impulse(var1) response(var2)
/* make some pretty impulse response graph(s) */
I ran the two set of code using the same data from the Matlab package. The results are similar.