Want to use InStr()in SilkTest Workbench 16

Want to use InStr()

I want to use some VB functions InStr, SubStr in SilkTest Workbench 16. It does not seem to be supported.

I added an imports Microsoft.VisualBasic to the script. Still nothing updated.

Are these functions natively available?

How can they be accessed?

What do others use in place of this for parsing out strings?

Thanks

Dan