Hi Anil,
Cash management and liquidity forecast reports are deriving its data mainly from Balance sheet items (Bank account/Bank clearing accounts) or Customer/vendor masterdata, as well as integration with other module such as SD (sales order), MM(requisition/PO), TRM (transaction) etc but not from actual spent P & L accounts automatically.
From my experience If the occurrence of these items are not that frequent, you can use a memo record together with creating new planning levels for each one and include into CM report.
If they are looking at deriving such information into Cash planning report, you need to look beyond the Cash management report but Liquidity forecast Actual report in SAP.
Hope that this helps
Taro