Budget approval workflow

Dear All,

Could you please advise me in budget approval workflow in PS only (Without using IM).

I want to trigger a workflow in PS as and when original budget value update (Using Transaction CJ30,CJ34,CJ35,CJ36,CJ37,CJ38) and after approving workflow I want to update value of budget in CJ32.

Anyone suggest me how could I achieve this business expectation.

P.S.  I tried to find workflow event in this transaction but not get any success.

Any kind of help is highly appreciable

Thanks.