SLED not updated in table LTAP ,LTBP

Dear gurus,

I am trying to maintain FIFO while dispatching material from wms managed warehouse.

For this i need SLED in table LTAP and LTBP.

But this field is not updated in above mentioned tables.

I have maintained shelf life in material master and I am also entering date of manufacture in GR.

But this value is not updated in TO, TR.

Kindly suggest on how to update this field.