Baby shower etiquette???

[ctea]

I'm planning a baby shower for a young woman who is like one of my own children. I have encountered some problems. Her mother lives 11 hours away but was planning on coming up next month and throwing a shower for her and her sister at the same time. I told my emotionally adoptive daughter that was find but I wanted to host one for her as well seperate from her sister. I'm not close with her sister or any of her family. I want to throw her the best baby shower ever. Becca, (the young woman this is about) has decided that she likes her baby shower being held seperate and has decided to invite her co-workers and freinds to the shower I'm throwing instead of to her moms. The shower I'm throwing is a month later than the one with her sister. This has upset her mom. Her mother feels like I'm interfereing. Now Becca is torn between her mom and me. I want the day to be all about Becca alone, not her sister who always gets more attention from her mom. more details coming.......
Beccas mom is wanting to hold her shower at Beccas sister house. To this isn't fair to Becca. Becca doesn't want to hurt her mom but she wants my shower. Any ideas on how to help her and smooth her moms ruffled feathers. Also We have rented a conference room at a hotel to hold her party in. Its not expensive either, only $100. They provide the complete set up, tables chairs, linens even skirting on teh tables. They do all teh clean up after. All we have to do is make sure all trash is in the cans. I love it. But Becca said we are spending too much on her. To me she is worth it and I'm enjoying planning this. Her home is too small and I don't want to have it at her sisters and I have to have it in a central location to all the guests so more will show up. Is it proper for the host to choose the location or is that usually up to the mom to be to decide location? She should just take what I'm doing as a gift of love. Any ideas how to over come these two problems?
lady_phoenix39. I've known this family for 20 years. Becca is close to me because her mother isn't. Becca spends holidays with us, not her own family by her choice. I'm always there for her and so is the rest of my family. My own daughter is exceptionally closer to her and my sons help her move when she moves. This is in a sense my first grand child and my oldest isn't the father but he and her used to date, are now best freinds and he intends to be part of the childs life and help Becca support the baby. I'm proud of him and I love the child simply because its part of Becca