I want add two new customPropertites in excel as the picture1 in attachment . the code as following.
``` workbook.DocumentSummaryInformation.CustomProperties = new CustomProperties();
workbook.DocumentSummaryInformation.CustomProperties.Add("ESG_TYPICAL", "EPLAN SCHEMATIC GENERATOR");
workbook.DocumentSummaryInformation.CustomProperties.Add("ESG_TYPICAL_VERSION", "1.8.10");
```
but result is I get nothing.
Comments: Not a bug
``` workbook.DocumentSummaryInformation.CustomProperties = new CustomProperties();
workbook.DocumentSummaryInformation.CustomProperties.Add("ESG_TYPICAL", "EPLAN SCHEMATIC GENERATOR");
workbook.DocumentSummaryInformation.CustomProperties.Add("ESG_TYPICAL_VERSION", "1.8.10");
```
but result is I get nothing.
Comments: Not a bug
