For sairose,
Here's one of your sister's chapter sites, the Theta Xi Chapter at Bethune-Cookman College. The SAI handsign is all over this page so you can take a look.
Theta Xi Chapter
The sorority call wasn't on there, but trust me they do have one.
GSS is the same way--we have a handsign and call, but not all of our chapters use it/know it. To be frank many of our AA chapters (including mine) use it more often and that may be the case with SAI too.