This question is best answered by PDF xchange since the options you are using would work the other way, that is from SumatraPDF you should be able to open a file FROM SumatraPDF in PDF exchange editor using the same
"%1" filename parameter and
/A page=%p for the current page.
e.g. in SumatraPDF settings.txt it would be
CommandLine = "C:\Program Files\Tracker Software\PDF Editor\PDFXEdit.exe" /A page=%p "%1"
Name = PDF XChange Editor
Filter = *.pdf
SumatraPDF expects the page number as -page # filename so I am guessing you need the PDF xchange Numero de Pagina %p symbol from its shown drop down
-page %p "%1"
note there is a space before -page
Remember when the file is open in both you may need to press R to reload and view after an edit and as with all editors to work on multiple files set
UseTabs = true and
ReuseInstance = true
There is also a filesize limit whist viewing and editing the same file
In SumatraPDF 3.1.2 the file is locked at 10 Mb
In Pre-Release it is now 32 Mb
If the file is larger you need to close it in SumatraPDF whilst saving edits.