Roth In Plan Conversion

Hello,

 

I signed up for Roth-In-Plan conversion last year and contributed some After-tax money towards it. My employer noted that amount on W2 as "401K After Tax Contribution".  I have not been sent 1099R or any other form regarding the same.

 

So, here's my questions:

1) Do I need to let IRS know about it? W2 has it, so IRS knows it already? 

2) How do I enter this information in Turbotax (Premier)? 

 

Thanks in advance for the help!