Apache 如何将新环境变量插入指令？

我在一台服务器上，唯一可以配置Apache的功能是通过.htaccess文件。因此，在Ubuntu Linux上不需要添加Apache模块，也不需要访问httpd.conf等Apache 2.2

我需要基于现有的环境变量创建一个新的环境变量

SetEnv my_new_var /debug/path/to/password/.passwd
SetEnvIf PREESTABLISHED_VAR "a" my_new_var=/first/path/to/password/.passwd
SetEnvIf PREESTABLISHED_VAR "b" my_new_var=/second/path/to/password/.passwd
AuthType basic
AuthName "User name"
AuthUserFile ???????
Require valid-user

我应该用AuthUserFile的值替换我的新变量的值来替换问号吗

AuthUserFile my_new_var

生成日志错误

No such file or directory: Could not open password file: /etc/apache2/my_new_var

AuthUserFile $my_new_var

No such file or directory: Could not open password file: /etc/apache2/$my_new_var

AuthUserFile ${my_new_var}

No such file or directory: Could not open password file: /etc/apache2/${my_new_var}

生成日志错误

No such file or directory: Could not open password file: /etc/apache2/my_new_var

AuthUserFile $my_new_var

No such file or directory: Could not open password file: /etc/apache2/$my_new_var

AuthUserFile ${my_new_var}

No such file or directory: Could not open password file: /etc/apache2/${my_new_var}

生成日志错误

No such file or directory: Could not open password file: /etc/apache2/my_new_var

AuthUserFile $my_new_var

No such file or directory: Could not open password file: /etc/apache2/$my_new_var

AuthUserFile ${my_new_var}

No such file or directory: Could not open password file: /etc/apache2/${my_new_var}

（作为不可能影响解决方案的旁注，身份验证是使用https而不是http提供的；密码文件位于文档系统之外；其中的密码是散列的。）