That option will be available in the paid version .
Now seriously, you just have to edit the trail.
Example, file prt2step.txt
!Export Step Files
~ Command `ProCmdModelSaveAs`
~ Update `file_saveas` `opt_EMBED_BROWSER_TB_SAB_LAYOUT` `C:\\Export\\Steps`
~ Activate `file_saveas` `opt_EMBED_BROWSER_TB_SAB_LAYOUT`
~ Select `file_saveas` `type_option` 1 `db_539`
~ Activate `file_saveas` `OK`
~ Activate `intf_export` `solids` 1
~ Activate `intf_export` `OkPushBtn`
Adding the two bold lines will define the destination directory. Just correct the path to yours.
Repeat for the other trails