dynamic query parameters?

nevermind, i found display_posts_shortcode_args

ok, i found the problem: inlike tags & categories, a taxonomy query must b built:

[tax_query] => Array (
		[0] => Array ( 
	 		[taxonomy] => genres 
	 		[field] => slug 
	 		[terms] => Array ( [0] => bad1 ) 
	 		[operator] => IN 
 			[include_children] => 1 
	 		) 
	 	)

tricky…but unfortunately php is not cooperating:-( i can build an array:

Array ( [taxonomy] => genres 
 	 [field] => slug 
 	 [terms] => Array ( [0] => bad1  ) 
 	 [operator] => IN [include_children] => 1 ) 

but the arrays seem to disappear: both [terms] & the enclosing [tax_query]
show empty Arrays:-\