Hi Puru,
I do not really understand your business case.
You have option of an the integrated purchasing process with IMAT and fixed asset creation.
In addition you have the manual process with posting the costs to a certain account and activate out of this account the fixed asset (here the linkage between purchase and Fixe Asset is lost). In all cases you have at least one IMAT and you have cost postings.
So I do not understand, what is your purpose.
Best regards
Marlene