Load function returning array or string from DLL created in Delphi

I'm trying to call a function from a 32-bit DLL created in Delphi. My (simplified) function is defined in Delphi like so:

library my; type TArrayOfReal = array of Real; function sumarrayreal(x,y : Real) : TArrayOfReal; begin SetLength(Result,3); Result[0]:=x; Result[1]:=y; Result[2]:=x+y; end; exports sumarrayreal; 

I'm using a special type TArrayOfReal here because Delphi functions (as far as I know) can't return arrays, not even static ones.

Then I call my DLL from a 64-bit version of Mathematica 11:

(*In*) Needs["NETLink`"] UninstallNET[] InstallNET["Force32Bit" -> True] fun1 = DefineDLLFunction["sumarrayreal", "my.dll", "double[]", {"double", "double"}] (*Out*) Function[Null, If[NETLink`DLL`Private`checkArgCount["sumarrayreal", {##1}, 2], Wolfram`NETLink`DynamicDLLNamespace`DLLWrapper2`sumarrayreal[##1], $Failed], {HoldAll}] 

When I try to use this function

(*In*) fun1[2., 3.] (*Out*) $Failed 

I receive an error:

A .NET exception occurred: "System.Runtime.InteropServices.MarshalDirectiveException: Cannot marshal 'return value': Invalid managed/unmanaged type combination.

Even a function that returns a string

(*delphi code*) function sumarray(x,y : Real) : string; begin Result := FloatToStr(x)+' '+FloatToStr(y) + ' '+ FloatToStr(x+y) end; (*Mathematica In*) fun2 = DefineDLLFunction["sumarray", "my.dll", "string", {"double", "double"}] 

doesn't work:

A .NET exception occurred: "System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

But a function that returns a single value DOES work:

(*delphi code*) function sum(x,y : Real) : Real; begin Result := x+y; end; (*In*) fun3 = DefineDLLFunction["sum", "my.dll", "double", {"double", "double"}] (*Out*) Function[Null, If[NETLink`DLL`Private`checkArgCount["sum", {##1}, 2], Wolfram`NETLink`DynamicDLLNamespace`DLLWrapper1`sum[##1], $Failed], {HoldAll}] (*In*) fun3[2., 3.] (*Out*) 5. 

The problem is that I absolutely need to return an array (or a string at worst), not a single value! What do I do with that? Thank you.