在发送请求时，确保将所需的声明作为子声明发送到ADFS服务器。可以使用以下代码示例创建ADFS令牌，并为其添加所需的子声明。

private static string GetToken()
{
    var authority = "https://adfs.server.com/adfs";
    var clientId = "{client-id}";
    var clientSecret = "{client-secret}";

    var clientCredential = new ClientCredential(clientId, clientSecret);
    var authenticationContext = new AuthenticationContext(authority);
    var userAssertion = new UserAssertion(token, "urn:ietf:params:oauth:grant-type:jwt-bearer");

    var result = await authenticationContext.AcquireTokenAsync("https://resource.server.com", clientCredential, userAssertion);

    var handler = new JwtSecurityTokenHandler();
    var token = handler.ReadJwtToken(result.AccessToken);

    var header = token.Header;
    var payload = token.Payload;

    var subClaim = payload.First(x => x.Key.Equals("sub")).Value.ToString();

    // Add custom claims
    var claims = new List
    {
        new Claim("custom_claim_1", "value_1"),
        new Claim("custom_claim_2", "value_2")
    };

    // Add sub claim
    claims.Add(new Claim("sub", subClaim));

    var tokenDescriptor = new SecurityTokenDescriptor
    {
        Subject = new ClaimsIdentity(claims),
        SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(Encoding.UTF8.GetBytes(clientSecret)), SecurityAlgorithms.HmacSha256Signature)
    };

    var securityTokenHandler = new JwtSecurityTokenHandler();
    var stoken = securityTokenHandler.CreateToken(tokenDescriptor);

    return securityTokenHandler.WriteToken(stoken);
}