There is a simple way implemented in SMath Studio to insert Greek characters inside the Text or Math regions in the worksheet:
To insert 'α' (Alpha) press 'a' and then press Ctrl+G.
To insert 'β' (Beta) press 'b' and then press Ctrl+G.
To insert 'γ' (Gamma) press 'g' and then press Ctrl+G.
To insert 'δ' (Delta) press 'd' and then press Ctrl+G.
To insert 'ε' (Epsilon) press 'e' and then press Ctrl+G.
To insert 'ζ' (Zeta) press 'z' and then press Ctrl+G.
To insert 'η' (Eta) press 'h' and then press Ctrl+G.
To insert 'θ' (Theta) press 'q' and then press Ctrl+G.
To insert 'ι' (Iota) press 'i' and then press Ctrl+G.
To insert 'κ' (Kappa) press 'k' and then press Ctrl+G.
To insert 'λ' (Lambda) press 'l' and then press Ctrl+G.
To insert 'μ' (Mu) press 'm' and then press Ctrl+G.
To insert 'ν' (Nu) press 'n' and then press Ctrl+G.
To insert 'ξ' (Xi) press 'x' and then press Ctrl+G.
To insert 'ο' (Omicron) press 'o' and then press Ctrl+G.
To insert 'π' (Pi) press 'p' and then press Ctrl+G.
To insert 'ρ' (Rho) press 'r' and then press Ctrl+G.
To insert 'σ' (Sigma) press 's' and then press Ctrl+G.
To insert 'τ' (Tau) press 't' and then press Ctrl+G.
To insert 'υ' (Upsilon) press 'u' and then press Ctrl+G.
To insert 'φ' (Phi) press 'f' and then press Ctrl+G.
To insert 'χ' (Chi) press 'c' and then press Ctrl+G.
To insert 'ψ' (Psi) press 'y' and then press Ctrl+G.
To insert 'ω' (Omega) press 'w' and then press Ctrl+G.
The same keystrokes for uppercase Greek characters.