Escape characters in variables

I have a an array of strings local variable Locals.Header. Each element should contain TAB characters, so I created these strings as they would be in expressions - where \t is a tab character after evaluation of the expression.

If I build a string with the STR() function from the array elements, all "\t"s appear in the print. But I need tabs. What is the reason and how to solve it?

Madottati