Hi Shivagi,
I didn't find any required is missed in your implementation. So that, I wondered that the Variant may already works , but you don't experience Variant execution due to no any actual difference between Variant customizing and original customizing.
I wet through the mentioned post, and it seems that the original structure mapping is also maintained for "USER_DETAILS" structure which is same as maintained in the variant.
I would suppose that the variant action AIF_T2/ACTION_VAR is the only valid variance.
Can you put a break-point in the action function (or even force a dump) in order to double confirm whether the variant works or not?
If it doesn't work, I suggest you to try a CHAR value instead of NUMC value (112)? I'm not sure if here is an ALPHA conversion issue.
Yaping