Transmission of Shares

My mother had left 199 shares of a company at the time of her death in 1977. The company had issued 99 bonus shares in 1978 ie after her death, totally 298 shares which we were holding in 1978.After 1978, we had shifted from our native place. Hence we were not aware of the bonus shares issued between 1978 and 1990. In 1990,I had applied for succession certificate for 298 shares and obtained from court .When I asked the company to transmit the shares in my name, the company asked me to amend /include the bonus shares issued in between. But my lawyer said that the succession certificate cannot be extended to include bonus shares but only for any other security left out /omitted at the time of applying for succession certificate. Further my lawyer says that Succession certificate covering shares held by a deceased member on the date of his death would cover subsequent issue of bonus shares and no fresh succession certificate would be required .H e also said that succession certificate can be obtained only for assets held at the time of death and not for any accrual or additions made after death. Please guide me for representing to the company or any other forum so that I can get the shares transmitted in my name as the matter is prolonging for a very long time.