In Open Calc, how do I copy a paste cells that contain references to other workbooks?

Question

I have an OpenOffice Calc sheet with cells containing formulas that refer to another file, e.g: 'file:///C:/path/to/other.xls'#$Sheet1.A1:B2.

When I copy the cells from one sheet to another in the same workbook, it works as expected. When I paste it into another workbook, the references are lost and all is left is ''#$Sheet1.A1:B2.

I could copy/paste the cell's contents, but that would be fastidious, error-prone, and anyhow not a good solution.

How do I keep the external references when copy-pasting from one workbook to another ?