decomposition of automorphisms of certain solvable subalgebra of symplectic lie algebra over commutative rings

Let Cl+1(R) be the 2(l+1)×2(l+1) matrix symplectic Lie algebra over a commutative ring R with 2 invertible. Then tl+1CR  =  {m-1m-20-m-1T ∣ m̅1 is an l+1 upper triangular matrix, m̅2T=m̅2,  over  R} is the solvable subalgebra of Cl+1(R). In this paper, we give an explicit description of the automorphism group of tl+1(C)(R).