Convert the following fixed format code from MS Dev Studio?

I would like to convert the following fixed format code from MS Developer Studio to free format in FTN95.

!        Special interface to use 32 bit Windows 'C' Library BTRCALL routine
!        contained in WBTRV32.LIB
         INTERFACE TO INTEGER*4 FUNCTION BTRCALL 
     + [STDCALL,ALIAS:'_BTRCALL@28' ](ARG1[VALUE]
     +                                        ,ARG2[REFERENCE]
     +                                        ,ARG3[REFERENCE]
     +                                        ,ARG4[REFERENCE]
     +                                        ,ARG5[REFERENCE]
     +                                        ,ARG6[VALUE]
     +                                        ,ARG7[VALUE])

         INTEGER*4     ARG1      
         CHARACTER*128 ARG2      
         CHARACTER*(*) ARG3      
         INTEGER*4     ARG4      
         CHARACTER*(*) ARG5      
         INTEGER*4     ARG6      
         INTEGER*4     ARG7      

	END

Should I be using C_EXTERNAL? Or maybe something similar to the following:

!Special interface to use 32 bit Windows 'C' Library BTRCALL routine
!contained in WBTRV32.LIB
interface
STDCALL BTRCALL '_BTRCALL@28' (VAL,REF,REF,REF,REF,VAL,VAL):INTEGER*4

INTEGER*4 arg1
CHARACTER (LEN=128) :: arg2
CHARACTER (LEN=*) :: arg3
INTEGER*4 arg4
CHARACTER (LEN=*) :: arg5
INTEGER*4 arg6
INTEGER*4 arg7
 
END FUNCTION BTRCALL
end interface

With this, I get a the following errors: Nesting error - the INTERFACE construct on line 3 has been terminated ARG3 cannot have the type CHARACTER (LEN=*) :: arg3 as it is not a dummy argument...

Any ideas on how to best handle this?

You will need STDCALL but not 'interface' before it. That is all. Nothing else after this line.

Thanks