自前のエクステンション使います。
サンプル
GraphicsWindow.BackgroundColor = "skyblue"
button = Controls.AddButton("run", 200, 100)
Controls.ButtonClicked = onclick
Sub onclick
C = Text.GetCharacter(34)
R = Text.GetCharacter(13) + Text.GetCharacter(10)
code = ""
code = code + "Function setup(a)" + R
code = code + "set reg = createObject(" + C + "VBScript.RegExp" + C + ")" + R
code = code + "reg.pattern = " + C + "a(.)c" + C + R
code = code + "set mc = reg.execute(" + C + "abc" + C + ")" + R
code = code + "if mc.count > 0 then" + R
code = code + "set smc = mc.item(0).submatches" + R
code = code + "msgbox smc.item(0)" + R
code = code + "setup = smc.item(0)" + R
code = code + "end if" + R
code = code + "End Function" + R
a = Class1.VBSrun(code)
EndSub