You can still use Set Variable Value, but set the Mode to Code Expression. You'll have to come up with a code expression to split the string.
Split it around the "." character, then grab the last element, split it around underscores and grab the first element. That's your sales ID
You could also grab it from earlier in the string with a different split.
You'll also have to make sure to use a project variable so its value doesn't get lost (I am not sure if variables on other keyword tests go out of scope)
