One way to do it.
Do your search in WTM. (I used right click in Gen 15:6 / Search on Lemma).
Then open Word List Manager (WLM) (quickest way is F8 key)
Click "Load or Generate Word List" button at bottom of WLM window.
On "Create Word List" window
set Version to WTM The result confirms your analysis, except that WTM has a separate code for qal pass, of which there is one instance.
select "Load highlighted words from last query"
select keep -- morph codes, and set the number to 2
click "Create list" button at bottom of window
Oops, sorry, I missed that you are in BW7. Unfortunately, BW7 only gives you the choice of all morph codes, or no morph codes. You need to be able to limit it to 2 codes.
(BW8 does allow you to specify number of morph codes)