C struct to C# struct

[Alvaro Enriquez de Luna]

Hello everybody. I am trying to use in C# a dll developed in C. I am
founding problems with C structs. While my C struct does not include
anything related with char or char *, everyting works ok, but when I
introduce a char or char * variable in the struct, I obtain a message
like this:

"Method's type signature is not PInvoke compatible."

Here is my code in both languages:

***************
C CODE
***************
struct _struct
{
int inte;
double doub;
float floa;
char charac;

};

__declspec(dlle xport) struct my_struct GiveMeStruct()
{
struct my_struct stru;

stru.inte=25;
stru.doub=3.141 592;
stru.floa=0.025 46f;
stru.charac='n' ;
return stru;

}

*************** ***
C# CODE
*************** ***
//////////////////////
Declaration:
//////////////////////

public struct my_struct
{
public int inte;
public double doub;
public float floa;
public char charac;
}

[DllImport("Reso urces/DLL/CCSS_DLL.dll")]
public static extern my_struct GiveMeStruct();

/////////////////////
Use: (i.e. after a button is pushed in a Form)
///////////////////

my_struct aux_estruct = DBManager.GiveM eStruct();

MessageBox.Show (aux_estruct.in te.ToString());
MessageBox.Show (aux_estruct.do ub.ToString());
MessageBox.Show (aux_estruct.fl oa.ToString());
MessageBox.Show (aux_estruct.ch arac.ToString() );

NOTE: Everything works until I add the 'charac' part in both sides, C
and C#.

Any ideas about how to do it? Thanks in advance.