You may try with this function I have modified time ago. I hope it works for you.
ps_load_initial_gamma.m (7.2 KB)
It should be used on the stamps step 1. So before you override the current one on the stamps_v4.1b/matlab/ please make a backup.
Then please run again the command stamps(1,1) so you re-run step1 to use this function
Let me know if this helps