Terminal session Send Keys activities : how to configure key in string

I’m using a connection to iSeries that works perfectly with SendcontrolKey activity.
But, I want to give the key in an argument (in place of harcoding it by choosing the value in a drop down list bok (cfr the picture)

I tried different approach with the SendKey activity.
[k{ENTER}] --> change automatically to %[k{ENTER}] in studio

Nothing append !

I know that an heavy solution could be to use an enormous switch but I can’t beleive that’s there is not an other solution.

Thank to all for your answer

I found the solution in the IBM documentation.
The keystroke must be enclosed between and must be lowercase.
eg .
[sysreq] for system request
[enter] for enter

Hoping that this post will help some of you.