This is the site for the owners manuals for the RBI Hawk 226VS:
http://www.hawkwoodworkingtools.com/WebsitePages/Scroll-Saw-Manuals.html. You will see that there are a number of variations on the 226VS. You will need your serial number from the saw to narrow it down to the correct manual.
I am not sure about the front to back movement, but it may be a function of the saw. I know some saws have a setting to make them more aggressive, not sure about the 226VS models, my Hawk G4 has such an adjustment. You may also want to read the information in that manual, which is the manual listed in the top left hand corner of the above web site.
I hope this helps, someone else may have better information regarding the 226 series.