BizTalk Mapper: If...Then...Else

It's unbelievable there is no a "If..Then..Else" functoid in BizTAlk Mapper, however, you can combine some functoid to archive it if you dislike to write any code.

Below is the solution for "If source node exist, Then directly link with distination node, Else set a null to destination node" :
1, Drag  a Logical Existence functoid and Value Mapping functoid onto the map surface, then connect them.

2, Drag a Logical NOT functoid and another Value Mapping functoid onto the map surface, then connect them.

As shown as below.

Another important thing is for Flattern Value Mapping(Yellow circle), in this case, if the parent Node or record (N_Name_S41) doesn't exist in source message, you would use Flattern Value Mapping, if not, you will get blank message when you test map.