I checked the microfilmed records of St. Rose of Lima Parish. The church was organized in 1909 and the records filmed are from 1910 to 1920. Anything after 1920 was not allowed to be filmed which meant their marriage record was not available.
I did find their names in the marriage index of the archives office as follows: Rose BRAUN, age 22, daughter of Joseph BRAUN and Susan STEFFEN license applied for April 1926, Alvin BAESEMANN, age 37, son of Henry BAESEMANN and Hulda LAST. The license was taken out in WASHINGTON county, #1390, 11-30. I find it interesting that they chose the Fredonia church rather than the Little Kohler church which I would have thought was probably closer to where they may have lived.
As I see it, you have two options. You could either write the Archdiocese of Milwaukee, attn: Timothy Cary, Archivist, 3501 South Lake Drive, Milwaukee, WI 53207 (414) 769-3408 requesting a copy and/or write to Washington County Register of Deeds, 432 E. Washington St., West Bend, WI 53095 (262) 338-4301 for a copy which you should be able to get easily as you have the license numbers.
Hope this helps. --Carol