PROC DSTRANS is undocumented because it is only intended for back-end use by other SAS procedures in very specific cases. In SAS 9.4 M6, PROC DSTODS2 is a documented procedure designed to help SAS users translate DATA step code to DS2. I wrote a blog post about this a while back.
One limitation is that both the original program file and the output file must reside in the current SAS default directory. In some client-server deployments, you won't have write permission to the SAS default directory. You can work around this by using the base SAS DLGCDIR function to set the default directory to a location where you do have write access. For example, if you were working in SAS on a Windows server and have write access to the c:\temp directory, you would save your DATA step program to C:\temp, then run code like this to make the translation:
%put %qsysfunc(dlgcdir(c:\temp));
PROC DSTODS2 IN="datastep.sas"
OUT="ds2program.sas";
RUN;
Hope this helps.
Mark