Pro-note

I had given Rs.10000 to my younger brother(agriculturalist) 4 years back for his urgent needs and for which I had received a signature in blank paper signed across the revenue stamp from him since he wasn't obeying me at that time. After my lending we both quarreled and he filed for a partition suit Two years nine months back including the properties of my first wife stating that those properties are owned from the income from the joint family undivided property, since I had been looking over and financing agricultural operations in our land for 3 years (my father died in 2000). My brother is giving me a lot of trouble to me now and he betrayed me and made me suffer heavy losses. Now I have filled the empty plain stamp affixed signed paper of my brother in a typed format for Rs.3,00,000 for 24% interest which he had given me 4 years back. Now I am going to put it as a pro-note in the court stating that he himself had executed it. I am also an income tax assesse. Will any problem arise(such as counter-blast) as the date I have typed in the pro-note comes after he had filed the partition suit? Is there any technology at present to find the exact month or a year a signature had been made by a person? Or any problems on filing of income tax returns in the past for money lent ? I also don't have any surety or attestation for this pro-note.