Mapping a network drive does not seem to work

[ReneNyffenegger]

Provide a description of requested docs changes

I am trying to map a network drive in the .wsb file with either

<MappedFolder>
     <HostFolder>\\10.72.147.203\o-map\path\to\tools</HostFolder>
    <SandboxFolder>C:\tools</SandboxFolder>
    <ReadOnly>true</ReadOnly>
</MappedFolder>

or

<MappedFolder>
    <HostFolder>p:\ath\to\tools</HostFolder>
    <SandboxFolder>C:\tools</SandboxFolder>
    <ReadOnly>true</ReadOnly>
</MappedFolder>

The .wsb file contains also:

 <Networking>Enable</Networking>

When I try to start the Sandbox with the ip number, I get the error message

Sandbox configuration failed. This may occur if invalid settings were supplied to the Sandbox. Error 0x80070005. Access is denied.

When using the variant with the drive letter, I get

Sandbox configuration failed. This may occur if invalid settings were supplied to the Sandbox. Error 0x80070003. The system cannot find the path specified.

Since I use credentials to access the drive that are different from that with which I am logged in, I assume this is the root of the problem.

Are there any pointers that help me access such a network drive?